Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 363 journals)
    - CERAMICS, GLASS AND POTTERY (31 journals)
    - MACHINERY (34 journals)
    - PACKAGING (19 journals)
    - PLASTICS (42 journals)
    - RUBBER (4 journals)


Showing 1 - 30 of 30 Journals sorted alphabetically
Advances in Applied Ceramics     Hybrid Journal   (Followers: 4)
Boletín de la Sociedad Española de Cerámica y Vidrio     Open Access   (Followers: 1)
Ceramics     Open Access  
Ceramics International     Hybrid Journal   (Followers: 25)
CeROArt     Open Access   (Followers: 1)
Challenging Glass Conference Proceedings     Open Access   (Followers: 7)
Crystal Growth & Design     Hybrid Journal   (Followers: 14)
Glass and Ceramics     Hybrid Journal   (Followers: 3)
Glass Technology - European Journal of Glass Science and Technology Part A     Full-text available via subscription   (Followers: 1)
International Journal of Applied Glass Science     Hybrid Journal   (Followers: 2)
International Journal of Ceramic Engineering & Science     Open Access   (Followers: 2)
Journal of Advanced Ceramics     Open Access   (Followers: 9)
Journal of Asian Ceramic Societies     Open Access  
Journal of Ceramics     Open Access   (Followers: 4)
Journal of Crystallization Process and Technology     Open Access   (Followers: 7)
Journal of Non-Crystalline Solids     Hybrid Journal   (Followers: 7)
Journal of Non-Crystalline Solids : X     Open Access  
Journal of the American Ceramic Society     Hybrid Journal   (Followers: 23)
Journal of the Australian Ceramic Society     Hybrid Journal  
Journal of The Chinese Ceramic Society     Open Access  
Journal of the European Ceramic Society     Hybrid Journal   (Followers: 15)
Journal of the Korean Ceramic Society : 한국세라믹학회지     Hybrid Journal  
Liquid Crystals Today     Hybrid Journal   (Followers: 1)
Molecular Crystals and Liquid Crystals     Hybrid Journal   (Followers: 1)
New Journal of Glass and Ceramics     Open Access   (Followers: 6)
Old Potter's Almanack     Open Access   (Followers: 1)
Open Ceramics     Open Access   (Followers: 2)
Powder Metallurgy and Metal Ceramics     Hybrid Journal   (Followers: 7)
Progress in Crystal Growth and Characterization of Materials     Full-text available via subscription   (Followers: 8)
Transactions of the Indian Ceramic Society     Partially Free   (Followers: 1)
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ISSN (Online) 2571-6131
Published by MDPI Homepage  [258 journals]
  • Ceramics, Vol. 6, Pages 1913-1925: Dielectric Properties of Compacts
           Sintered after High-Pressure Forming of Lithium Fluoride

    • Authors: Pavel Ctibor, Libor Straka, Josef Sedláček, František Lukáč
      First page: 1913
      Abstract: High-pressure forming at 300 MPa and room temperature was applied before the sintering of a lithium fluoride (LiF) powder. The as-fired samples were tested as dielectrics and showed very interesting characteristics. The best sample, sintered at 750 °C for 8 h, had a relative permittivity of 12.1 and a loss tangent of 0.0006, both of them frequency-independent and temperature-independent up to at least 150 °C, and moreover, the volume DC resistivity was 27.4 × 1012 Ωm at room temperature. These parameters are comparable with oxide ceramics, processed at temperatures over 1300 °C, as for example, aluminum dioxide (Al2O3) or Y3Al5O12 (YAG). LiF material is advantageous because of its very low sintering temperature, which is only about one-half of typical oxide ceramic dielectrics.
      Citation: Ceramics
      PubDate: 2023-09-22
      DOI: 10.3390/ceramics6040118
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 1926-1936: Characterization and Heat Transfer
           Assessment of CuO-Based Nanofluid Prepared through a Green Synthesis

    • Authors: Suresh Kumar Shanmugam, Ajithram Arivendan, Samy Govindan Selvamani, Thangaraju Dheivasigamani, Thirumalai Kumaran Sundaresan, Saood Ali
      First page: 1926
      Abstract: The manufacturing of copper oxide (CuO) nanoparticles has been accomplished utilizing a green technique that relies on biologically reliable mechanisms. Aqueous solutions of copper nitrate and Ixora Coccinea leaf extract are used in an environmentally safe process for creating CuO nanoparticles. The characterization of the synthesized CuO nanoparticles involves the utilization of techniques such as X-ray diffractometry (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetricanalysis (TGA). CuO nanoparticles are confirmed by XRD and FTIR peak results. When the particles are measured, they range between 93.75 nm and 98.16 nm, respectively. The produced CuO nanoparticles are used to prepare the nanofluid. While conventional water exhibits a 3 °C temperature difference, nanofluid achieves a considerable temperature differenceof 7 °C. As a result, it is clear that the nanofluid performs better at dispersing heat into the environment. The experiment’s overall findings support the possibility of ecologically friendly, green-synthesized CuO nanoparticle-induced nanofluid as an effective heattransfer fluid that can be applied to heattransfer systems.
      Citation: Ceramics
      PubDate: 2023-09-22
      DOI: 10.3390/ceramics6040119
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 1937-1977: Rare-Earth Doped Gd3−xRExFe5O12
           (RE = Y, Nd, Sm, and Dy) Garnet: Structural, Magnetic, Magnetocaloric, and
           DFT Study

    • Authors: Dipesh Neupane, Noah Kramer, Romakanta Bhattarai, Christopher Hanley, Arjun K. Pathak, Xiao Shen, Sunil Karna, Sanjay R. Mishra
      First page: 1937
      Abstract: The study reports the influence of rare-earth ion doping on the structural, magnetic, and magnetocaloric properties of ferrimagnetic Gd3−xRExFe5O12 (RE = Y, Nd, Sm, and Dy, x = 0.0, 0.25, 0.50, and 0.75) garnet compound prepared via facile autocombustion method followed by annealing in air. X-Ray diffraction (XRD) data analysis confirmed the presence of a single-phase garnet. The compound’s lattice parameters and cell volume varied according to differences in ionic radii of the doped rare-earth ions. The RE3+ substitution changed the site-to-site bond lengths and bond angles, affecting the magnetic interaction between site ions. Magnetization measurements for all RE3+-doped samples demonstrated paramagnetic behavior at room temperature and soft-ferrimagnetic behavior at 5 K. The isothermal magnetic entropy changes (−ΔSM) were derived from the magnetic isotherm curves, M vs. T, in a field up to 3 T in the Gd3−xRExFe5O12 sample. The maximum magnetic entropy change (−∆SMmax) increased with Dy3+ and Sm3+substitution and decreased for Nd3+ and Y3+ substitution with x content. The Dy3+-doped Gd2.25Dy0.75Fe5O12 sample showed −∆SMmax~2.03 Jkg−1K−1, which is ~7% higher than that of Gd3Fe5O12 (1.91 Jkg−1K−1). A first-principal density function theory (DFT) technique was used to shed light on observed properties. The study shows that the magnetic moments of the doped rare-earths ions play a vital role in tuning the magnetocaloric properties of the garnet compound.
      Citation: Ceramics
      PubDate: 2023-09-22
      DOI: 10.3390/ceramics6040120
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 1977-1990: Microstructure, Mechanical and Thermal
           Properties of ZTA/Al2TiO5 Ceramic Composites

    • Authors: A. M. Hassan, Hamada Elsayed, M. Awaad, A. M. Saleh, S. M. Naga
      First page: 1977
      Abstract: Zirconia-toughened alumina (ZTA)/Al2TiO5 composites were prepared via a sol–gel route. The prepared samples were uniaxially pressed and pressurelessly sintered at 1650–1700 °C for 1 h. The microstructure, densification, and X-ray diffraction patterns of the sintered ZTA/Al2TiO5 composites were investigated, and their mechanical properties, thermal coefficient, and shock resistance were characterized. The addition of Al2TiO5 hindered the grain growth of the alumina particles and enhanced the relative density, Vickers hardness, and bending strength of the composites compared with pure ZTA samples. The fracture toughness was improved by 19% upon the addition of 40 wt% Al2TiO5. Moreover, increasing the Al2TiO5 content resulted in an improvement in the thermal shock resistance.
      Citation: Ceramics
      PubDate: 2023-10-04
      DOI: 10.3390/ceramics6040121
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 1991-2007: Frequency Characteristics of High
           Strain Rate Compressions of Cf-MWCNTs/SiC Composites

    • Authors: Kun Luan, Chen Ming, Xiaomeng Fang, Jianjun Liu
      First page: 1991
      Abstract: The incorporation of ductile reinforcements into ceramics helps restrain crack deflection, which can enhance ceramics’ toughness and overcome the matrix’s brittleness. In this paper, we produced a ceramic composite reinforced by carbon fibers coated by multi-wall carbon nanotubes (shortened by Cf-MWCNT/SiC composites) for enhanced impact resistance at a high strain rate that commonly occurs in composite materials used in astronautics, marine, and other engineering fields. The fabrication process involves growing multi-wall carbon nanotubes (MWCNTs) on a carbon fiber woven fabric (Cf) to create the fibril/fabric hybrid reinforcement. It is then impregnated by polymer solution (precursor of the ceramics), forming composites after the pyrolysis process, known as the liquid polymer infiltration and pyrolysis (PIP) technique. To assess the impact resistance of the Cf-MWCNT/SiC under high-strain rate compressions, the split Hopkinson pressure bar (SHPB) technique is employed. Since the failure behavior of the Cf-MWCNT/SiC composites in the absence of the ductile phase is not well understood, the study employs the Hilbert–Huang transform (HHT) to analyze the stress–time curves obtained from the SHPB experiments. By applying the HHT, we obtained the frequency–time spectrum and the marginal Hilbert spectrum of the stress signals. These analyses reveal the frequency characteristics of the Cf-MWCNT/SiC composite and provide insights into the relationship between transformed signal frequency and fracture behavior. By understanding the dynamic fracture behavior and frequency response of the Cf-MWCNT/SiC, it becomes possible to enhance its impact resistance and tailor its performance for specific protective requirements. Therefore, the findings of this study can guide the future design and optimization of Cf-MWCNT/SiC structures for various protective applications, such as body armor, civil structures, and protections for vehicles and aircraft.
      Citation: Ceramics
      PubDate: 2023-10-05
      DOI: 10.3390/ceramics6040122
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2008-2017: Chemical Compositions of Chinese Glazed
           Tiles from an Imperial Mausoleum of the Liao Dynasty

    • Authors: Lan Zhao, Xiongfei Wan, Baoqiang Kang, He Li
      First page: 2008
      Abstract: Glazed tiles are characteristic architectural ceramics traditionally used in ancient Chinese royal buildings. Studies on their chemical compositions have provided valuable information regarding their compositional classifications and the provenances of their raw materials. Existing studies have mainly focused on the Yuan dynasty (1271–1368 AD) or later. Research on earlier ages is limited because of a lack of samples. In this study, we used an energy-dispersive X-ray fluorescence spectrometer to analyze the chemical compositions of 18 glazed tiles unearthed from an imperial mausoleum (the Xinli site) from the Liao dynasty (969–982 AD). The glazes of the tiles had a SiO2–Al2O3–PbO ternary oxidic system and the bodies of the tiles had a SiO2–Al2O3 binary oxidic system. Certain compositional differences were observed among the samples with different types of decorations. Compared with samples from the Yuan dynasty and later periods, the Xinli samples had higher SiO2 and Al2O3 contents and lower PbO and CuO contents in the tile glazes. The tile bodies of the Xinli samples had compositions similar to those of tile bodies from the Qing dynasty (1616–1912 AD). We speculated that the Xinli samples with different decorations came from different kiln sites.
      Citation: Ceramics
      PubDate: 2023-10-05
      DOI: 10.3390/ceramics6040123
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2018-2035: Dynamic Extrusion Control in Spot
           Deposition Modeling for Porous 3D Clay Structures

    • Authors: Vesela Tabakova, Christina Klug, Thomas H. Schmitz
      First page: 2018
      Abstract: The dynamic state of the viscous clay in Liquid Deposition Modeling (LDM) often leads to discrepancies between the digital model and the resulting physical object. This emergent behavior can be harnessed to produce complex physical structures that would not be possible with other methods. This study takes advantage of the viscous state and tensile strength of the extruded clay strand to explore the impact of dynamic extrusion and deformations through travel paths in LDM to manufacture complex porous physical structures. The effects of these parameters are discussed in two case studies: (1) regular and semi-random Spot Deposition surfaces with either open or thickened regions, and (2) porous 3D lattice structures created through the controlled bending of vertical extrusions. The achieved higher geometrical complexity of objects through the algorithmically programmed alternations in the sequence and rate of material deposition allows for a wide range of buildup approaches that expand the production spectrum of sustainable small- and large-scale elements.
      Citation: Ceramics
      PubDate: 2023-10-06
      DOI: 10.3390/ceramics6040124
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2036-2052: The Feature Resolution and Dimensional
           Control in Freeform Solidification of Alumina Systems by Stereolithography

    • Authors: Mustafa K. Alazzawi, Chawon Hwang, Victoria R. Tsarkova, Richard A. Haber
      First page: 2036
      Abstract: Controlling the feature resolution and dimension of printed products using stereolithography requires a comprehensive understanding of compositional and printing variables. Balancing these variables adds more complexity to manufacturing near net shape products. In this study, the compositional variables examined include particle size and solid content using two resins, and printing variables include layer thickness and energy dose. Choosing the energy dose for curing depends on compositional variables and consequently affects the degree of scattering. The results shows that light scattering determines the changes in the feature resolution and lateral dimensions. The layer thickness only affects the feature resolution and not the lateral dimensions. The vertical dimension does not significantly change with the chosen variables. In this study, fine-tuning the variables is shown to produce parts with high precision and resolution. Both compositional and printing variables play a key role in achieving near net shape products.
      Citation: Ceramics
      PubDate: 2023-10-17
      DOI: 10.3390/ceramics6040125
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2053-2069: Size-Independent Flexure Test Technique
           for the Mechanical Properties of Geocomposites Reinforced by
           Unidirectional Fibers

    • Authors: Hung Tran Doan, Dora Kroisova, Oleg Bortnovsky
      First page: 2053
      Abstract: In assessing the bending attributes for geopolymer composites augmented with uni-directional fibers, methodologies aligned with the established American and European standards yield quantifiable values for flexural strength, denoted as σm*, and its corresponding elasticity modulus, E*. Notably, these values exhibit a pronounced dependency on the size of the testing parameters. Specifically, within a judicious range of support span L relative to specimen height H, spanning a ratio of 10 to 40, these metrics can vary by a factor between 2 and 4. By conducting evaluations across an extensive array of H/L ratios and adhering to the protocols set for comparable composites with a plastic matrix, it becomes feasible to determine the definitive flexural elastic modulus E and shear modulus G, both of which can be viewed as size-neutral material traits. A parallel methodology can be employed to deduce size-agnostic values for flexural strength, σm. The established linear relationship between the inverse practical value E* (1/E*) and the squared ratio (H/L)2 is acknowledged. However, a congruent 1/σm* relationship has been recently corroborated experimentally, aligning primarily with Tarnopolsky’s theoretical propositions. The parameter T, defined as the inverse gradient of 1/σm* about (H/L)2, is integral to these findings. Furthermore, the significance of the loading displacement rate is underscored, necessitating a tailored consideration for different scenarios.
      Citation: Ceramics
      PubDate: 2023-10-17
      DOI: 10.3390/ceramics6040126
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2070-2085: The Effect of the Addition of Aluminum
           Nitride to the Composition of NiAl2O4 Ceramics on Hydrogenation Processes
           and the Increase in Resistance to Swelling and Degradation

    • Authors: Artem L. Kozlovskiy
      First page: 2070
      Abstract: This work examines the effects of the formation of impurity inclusions in the structure of NiAl2O4 ceramics when aluminum nitride is added to them and the occurrence of a reinforcement effect that prevents hydrogenation processes and the subsequent destruction of conductive and thermophysical characteristics. The appeal of ceramics possessing a spinel crystal structure lies in their potential use as ceramic fuel cells for both hydrogen generation and storage. Simultaneously, addressing the challenges related to ceramic degradation during hydrogenation, a critical aspect of hydrogen production, can enhance the efficiency of these ceramics while lowering electricity production costs. The selection of aluminum nitride as an additive for ceramic modification is based on its remarkable resistance to structural damage accumulation, its potential to enhance resistance to high-temperature degradation, and its ability to bolster strength properties. Moreover, an examination of the alterations in the strength characteristics of the examined samples subjected to hydrogenation reveals that the stability of two-phase ceramics is enhanced by more than three to five times compared to the initial ceramics (those without the addition of AlN). Additionally, it was noted that the most significant alterations in both structure and strength become apparent at irradiation fluences exceeding 1014 proton/cm2, where atomic displacements in the damaged ceramic layer reach over 5 dpa. During the evaluation of thermophysical properties, it was discerned that ceramics featuring an impurity phase in their composition exhibit the highest stability. These ceramics demonstrated a reduction in the thermal conductivity coefficient of less than 1% at the peak irradiation fluence.
      Citation: Ceramics
      PubDate: 2023-10-19
      DOI: 10.3390/ceramics6040127
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2086-2097: One-Step Microwave Synthesis of New
           Hybrid Phosphor (CSSC) for White Light-Emitting Diodes

    • Authors: Maxim Sychov, Mariia Keskinova, Andrey Dolgin, Igor Turkin, Kazuhiko Hara, Hiroko Kominami
      First page: 2086
      Abstract: The possibility of synthesizing a new hybrid phosphor CSSC (mixture of 0.5 CaSrSiO4:Eu2+: 0.29 Ca6Sr4Si6O21Cl2:Eu2+: 0.21 Ca10Si6O21Cl2:Eu2+) using a one-step microwave synthesis method is demonstrated. The concentrations of europium and calcium in the synthesized phosphors were optimized at 1 and 10 mol. %, respectively, to achieve maximum brightness and color rendering index. The optimal conditions for the synthesis of phosphors in a microwave furnace were determined as 750 °C for 10 min. The resulting phosphor exhibited a wide luminescence spectrum that covered the entire visible region, resulting in a high color rendering index and a warm white luminescence when used as a light source. It is shown that the sol–gel method for preparing the charge mixture for the new phosphor allows for a 35% higher luminescence brightness compared to the solid-phase method, due to a more uniform distribution of the activator.
      Citation: Ceramics
      PubDate: 2023-10-19
      DOI: 10.3390/ceramics6040128
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2098-2116: Electron-Beam Processing of
           Aluminum-Containing Ceramics in the Forevacuum Pressure Range

    • Authors: Aleksandr Klimov, Ilya Bakeev, Aleksey Zenin
      First page: 2098
      Abstract: Aluminum–ceramic materials based on Al2O3 and AlN are widely used in the electronics industry and, according to a number of electrophysical and technical and economic parameters, are among the most suitable for the production of electrical and radio engineering products. In this study, it is shown that the treatment of ceramics based on Al2O3 with an electron beam with a power of 200–1100 W and a current of 10–50 mA leads to heating of the ceramic surface to a temperature of 1700 °C. When heated to a temperature of 1500 °C and kept at this temperature for no more than 10 s, an increase in the roughness of the ceramic surface is observed by more than an order of magnitude. At the same time, for ceramic substrates based on aluminum nitride, an increase in the temperature of electron beam treatment from 1300 to 1700 °C leads to an increase in thermal conductivity from 1.5 to 2 times. The edge angle of water wetting of the AlN surface can vary from 20 to 100 degrees depending on the processing temperature, which allows one to control the transition of the material from a hydrophilic to a hydrophobic state. At the same time, electron beam exposure to Al2O3 does not change the wettability of this material so much. Electron beam processing in the forevacuum pressure region allows controlled changes in the electrophysical properties of ceramic materials based on Al2O3 and AlN.
      Citation: Ceramics
      PubDate: 2023-10-23
      DOI: 10.3390/ceramics6040129
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2117-2133: Bioinspired Mechanical
           Materials—Development of High-Toughness Ceramics through
           Complexation of Calcium Phosphate and Organic Polymers

    • Authors: Tadashi Mizutani, Natsuki Okuda
      First page: 2117
      Abstract: Inspired by the process of bone formation in living organisms, many studies have been conducted to develop organic–inorganic composite materials by preparing calcium phosphate crystals within solutions or dispersions of polymers with appropriate functional groups. Bones are composite materials consisting of organic polymers (mainly type I collagen), carbonated apatite, and water, with volume fractions of 35–45%, 35–45%, and 15–25%, respectively. Carbonated apatite in bone contributes to rigidity, while organic polymers and water contribute to toughness. The inorganic crystal, carbonated apatite, is a plate-shaped crystal with dimensions of 50 nm × 25 nm × 1–4 nm, generating a significant organic–inorganic interface, due to its nanoscale size. This interface is believed to absorb externally applied forces to dissipate mechanical energy to thermal energy. Creating such nanometer-scale structures using top-down approaches is challenging, making bottom-up methods, such as the coprecipitation of polymer and inorganic crystals, more suitable. In this account, efforts to develop eco-friendly mechanical materials using biomass, such as cellulose and starch, based on the bottom-up approach to bone-like composites are described.
      Citation: Ceramics
      PubDate: 2023-10-30
      DOI: 10.3390/ceramics6040130
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2134-2147: Ceramic Filters for the Efficient
           Removal of Azo Dyes and Pathogens in Water

    • Authors: Marvellous Oaikhena, Abimbola E. Oluwalana-Sanusi, Puseletso P. Mokoena, Nonhlangabezo Mabuba, Themba Tshabalala, Nhamo Chaukura
      First page: 2134
      Abstract: Overcoming the scarcity of safe and sustainable drinking water, particularly in low-income countries, is one of the key challenges of the 21st century. In these countries, the cost of centralized water treatment facilities is prohibitive. This work examines the application of low-cost ceramic filters as point-of-use (POU) devices for the removal of methylene blue, o-toluidine blue, Staphylococcus aureus, and Staphylococcus typhi from contaminated water. The ceramic filters had typical kaolinite functional groups, making them suitable for the removal of dyes and pathogens. Surface charge measurements indicated strongly anionic filters, while thermal properties confirmed the carbonization of the biowaste additive leaving behind a porous kaolinite structure which subsequently dehydroxylated into meta kaolinite. In addition, morphological data showed heterogeneous filter surfaces. Increased biomass content improved the permeability, water adsorption, flow rate, and apparent porosity of the filter. The ceramic filter removed methylene blue (42.99–59.74%), o-toluidine (79.95–92.71%), Staphylococcus aureus (98–100%), and Staphylococcus typhi (75–100%). Overall, the study demonstrated the effectiveness of POU ceramic filters in removing organic pollutants in contaminated water while serving as disinfectants.
      Citation: Ceramics
      PubDate: 2023-11-09
      DOI: 10.3390/ceramics6040131
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2148-2161: Preparation and Characterization of
           Freeze-Dried β-Tricalcium Phosphate/Barium Titanate/Collagen
           Composite Scaffolds for Bone Tissue Engineering in Orthopedic Applications

    • Authors: Dwi Fortuna Anjusa Putra, Bramantyo Bayu Aji, Henni Setia Ningsih, Ting-Wei Wu, Akihiro Nakanishi, Toshihiro Moriga, Shao-Ju Shih
      First page: 2148
      Abstract: The freeze-drying method creates a scaffold with a composite mesoporous structure with many advantages. However, everyday materials such as β-tricalcium phosphate (β-TCP) have been used as an orthopedic implant for canine tribal bone defects for decades, for instance, for grafting material of even shapes to form an implant for our teeth. However, this material is still not entirely expected to be the best implant due to its high biodegradability. Besides that, using the piezoelectric effect on the bone can lead to more efficiency in cell growth and a faster healing time for patients. Based on this phenomenon, a scaffold composite with a piezoelectric material such as barium titanate (BaTiO3/BT) has been tested. Based on the BT/β-TCP ratio, the scaffold composite of BT and β-TCP produces a porous structure with porosity ranging from 30.25 ± 11.28 to 15.25 ± 11.28 μm. The BT/β-TCP ratio influences the samples’ pore type, which affects each sample’s mechanical properties. In our result, the scaffold of 45.0 wt% BT/45.0 wt% β-TCP/10.0 wt% collagen has achieved a significant value of 0.5 MPa for maximum stress with a sufficient pore size of 25.32 ± 8.05 μm. Finally, we performed a viability test to see the sample’s piezoelectric effect, which showed that the piezoelectric effect does increase bone healing time when tested by growing MC3T3-E1 cells on the samples.
      Citation: Ceramics
      PubDate: 2023-11-11
      DOI: 10.3390/ceramics6040132
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2162-2177: Biomechanical Behavior of
           Lithium-Disilicate-Modified Endocrown Restorations: A Three-Dimensional
           Finite Element Analysis

    • Authors: Fatien I. Al-naqshabandi, Bahar Jaafar Selivany, Abdulsalam Rasheed Al-zahawi
      First page: 2162
      Abstract: This study aimed to assess the biomechanical behavior of endocrown-restored mandibular molars according to “margin design” and “coverage extent” using finite element analysis (FEA). Six 3D solid models were fabricated, namely, those with complete occlusal coverage: A (butt joint), B (anatomic margin); partial coverage (two mesial cusps): C (butt joint), D (anatomic margin); and partial coverage with mesial class II cavity: E (butt joint), F (anatomic margin). All models received lithium disilicate endocrowns (2.0 mm thickness and 4.0 mm central retainer cavity depth). A 300 N vertical load was applied to the occlusal surface, while a 250 N oblique load was applied at 45° to the lingual inclined planes of the buccal cusps. The maximum von Mises stress (VMS) distribution patterns were calculated for the endocrown, tooth structure, and cement layer. The VMS on the prepared teeth and cement layer showed subtle differences between the tested models under vertical loads. The anatomic margin (partial and complete coverage) exhibited a more homogeneous stress distribution and offered a more adhesive area of the tooth structure. Under oblique loading, the anatomic margin (complete and partial), except Model D, exhibited the lowest VMS in the cement layer. An anatomically based endocrown could be a promising alternative to the butt joint design, providing better-devised endocrown restorations, which could potentially yield a more benign stress dissipation.
      Citation: Ceramics
      PubDate: 2023-11-11
      DOI: 10.3390/ceramics6040133
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2178-2212: Non-Invasive On-Site XRF and Raman
           Classification and Dating of Ancient Ceramics: Application to 18th and
           19th Century Meissen Porcelain (Saxony) and Comparison with Chinese

    • Authors: Philippe Colomban, Gulsu Simsek Franci, Mareike Gerken, Michele Gironda, Viviane Mesqui
      First page: 2178
      Abstract: The authentication and dating of rare ceramics is generally carried out using subjective criteria, mainly based on visual interpretation. However, the scientific study and evaluation of the materials used could contribute objectively. The analytical data relating to the major and minor elements of the coloring agents of the decoration or the base marks, and the characteristics of the raw materials (related to geology and ore processing), can be obtained on the conservation site non-invasively using a pXRF instrument and the phases formed may be identified using Raman microspectroscopy. This approach is applied to 28 objects assigned to the production of the Meissen Factory, from the collection of the Musée National de Céramique, Cité de la Céramique, Sèvres. They have polychromic or blue-and-white decorations and are supposed to have been produced in the 18th and 19th centuries. Some have a production date that has been perfectly established, others may have been produced using an earlier mold, or even have been decorated on an unknown date different from that of the firing of the biscuit. The combination of several classification criteria concerning the type of glaze, previously identified in the study of French and Chinese 17th and 18th centuries productions, i.e., the elements associated with cobalt present in the mark or the blue decoration and the relative levels of impurities of the glaze matrix, both characteristic of the raw materials and giving a strong XRF signal, leads to the identification of groups of homogeneous objects (respectively, counting seven, three, two and two objects for which at least four out of five criteria are identical); the other objects present too many differences to be considered as having been produced with the same raw materials. The first group brings together almost all the objects with a reliable pedigree made before ~1750, but includes two objects with decoration types closer to those of the 1800s. The comparison of the pXRF signals confirms the possibility of identifying the use of European ingredients for the production of painted enamels in the Qing dynasty.
      Citation: Ceramics
      PubDate: 2023-11-12
      DOI: 10.3390/ceramics6040134
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2213-2242: High-Lead Glazed Ceramic Production in
           Western Iberia (Gharb al-Andalus) between the 10th and Mid-13th Centuries:
           An Approach from the City of Évora (Portugal)

    • Authors: Carlos Andrés Camara, María José Gonçalves, José Antonio Paulo Mirão, Susana Gómez Martínez, Massimo Beltrame
      First page: 2213
      Abstract: In the present study an archaeometry programme has been developed on a limited number of coarse wares, monochrome, and bichrome glazed ceramics retrieved in the cities of Évora, Mértola, and Silves, located in Western Iberia, Portugal (Gharb al-Andalus during the Islamic period). The goals were to shed light on glazed ceramics provenance, technology, trading, and on the glaze technology applied. For this purpose, a multi-analytical approach was employed to characterize ceramic pastes and glazes using optical microscopy (OM), X-ray diffraction (XRD), X-ray fluorescence (XRF), and a Scanning Electron Microscope coupled to an Energy Dispersive Spectrometer (SEM-EDS). Results evidenced that over the Islamic rule, coarse wares were locally produced at Évora. On the contrary, monochrome and bichrome glazed ceramics were imported from the city of Silves, Mértola, and from unidentified workshops, probably located in southern Iberia. The analysis of decorations evidenced that despite the provenance of the samples, the glaze technology applied was rather uniform over time, depicting a widespread technological transfer in the al-Andalus.
      Citation: Ceramics
      PubDate: 2023-11-15
      DOI: 10.3390/ceramics6040135
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2243-2255: Coextrusion of Clay-Based Composites:
           Using a Multi-Material Approach to Achieve Gradient Porosity in 3D-Printed

    • Authors: Julian Jauk, Hana Vašatko, Lukas Gosch, Kristijan Ristoski, Josef Füssl, Milena Stavric
      First page: 2243
      Abstract: 3D printing of ceramics has started gaining traction in architecture over the past decades. However, many existing paste-based extrusion techniques have not yet been adapted or made feasible in ceramics. A notable example is coextrusion, a common approach to extruding multiple materials simultaneously when 3D-printing thermoplastics or concrete. In this study, coextrusion was utilized to enable multi-material 3D printing of ceramic elements, aiming to achieve functionally graded porosities at an architectural scale. The research presented in this paper was carried out in two consecutive phases: (1) The development of hardware components, such as distinct material mixtures and a dual extruder setup including a custom nozzle, along with software environments suitable for printing gradient materials. (2) Material experiments including material testing and the production of exemplary prototypes. Among the various potential applications discussed, the developed coextrusion method for clay-based composites was utilized to fabricate ceramic objects with varying material properties. This was achieved by introducing a combustible as a variable additive while printing, resulting in a gradient porosity in the object after firing. The research’s originality can be summarized as the development of clay-based material mixtures encompassing porosity agents for 3D printing, along with comprehensive material-specific printing parameter settings for various compositions, which collectively enable the successful creation of functionally graded architectural building elements. These studies are expected to broaden the scope of 3D-printed clay in architecture, as it allows for performance optimization in terms of structural performance, insulation, humidity regulation, water absorption and acoustics.
      Citation: Ceramics
      PubDate: 2023-11-17
      DOI: 10.3390/ceramics6040136
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2256-2268: Effect of Ferrule Design on Stress
           Distribution of Maxillary Incisor Rehabilitated with Ceramic Crown and
           PEEK Post–Core Material: A 3D Finite Element Analysis

    • Authors: Laura H. J. Alberto, Zhaoxu Zhang, Yuanyuan Duan
      First page: 2256
      Abstract: Endodontic-treated teeth with massive degrees of coronal tissue loss usually require rehabilitation with post-retained unitary crowns. This study aimed to evaluate the effect of ferrule design on the stress distribution of maxillary incisors rehabilitated with zirconia crowns using finite element analysis. Six three-dimensional models were generated according to the presence and location of ferrule (No Ferrule, Buccal Ferrule, Lingual Ferrule, Buccolingual Ferrule, and Full Ferrule). The post–core materials tested were Nickel–chromium (NiCr) and Polyetheretherketone (PEEK). A static load of 100 N at a 45-degree angle on the Lingual surface, in a region 2 mm below the incisive ridge, was applied. Von Mises stresses and contour plots of all of the models were collected and analyzed. A lower and more uniform stress distribution was observed in the Full Ferrule model compared with the remaining models. A reduction of 72% in the von Mises peak stresses was observed in the root when comparing the Full Ferrule and No Ferrule models, both with PEEK post–core material. In conclusion, the presence of an incomplete ferrule is beneficial to the stress distribution in restored post-retained crowns. The use of PEEK for post–core structures reduces the stress concentration on the posts, reducing the predisposition to irreparable root fracture.
      Citation: Ceramics
      PubDate: 2023-11-20
      DOI: 10.3390/ceramics6040137
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2269-2281: Inorganic Green Pigments Based on

    • Authors: Kazuki Yamaguchi, Akari Takemura, Saki Furumoto, Ryohei Oka, Toshiyuki Masui
      First page: 2269
      Abstract: La1.03Sr1.97Al0.97M0.03O5 (M = Fe, Co, Ni, and Cu) samples were synthesized using a citrate sol–gel method to develop a novel environmentally friendly inorganic green pigment. Among them, the Co-doped sample exhibited a vivid yellow, but not green. Then, (La0.94Ca0.06)Sr2(Al0.97Mn0.03)O5 was synthesized and characterized with respect to the crystal structure, optical properties, and color. The sample was obtained in a single-phase form and the lattice volume was smaller than that of the (La0.94Ca0.06)Sr2AlO5 sample, indicating that Mn ions in the lattice of the sample were pentavalent. The sample exhibited optical absorption at a wavelength below 400 nm and around 650 nm. These absorptions were attributed to the ligand, the metal charge transfer (LMCT), and d-d transitions of Mn5+. Because the green light corresponding to 500 to 560 nm was reflected strongly, the synthesized sample exhibited a bright green color. (La0.94Ca0.06)Sr2(Al0.97Mn0.03)O5 showed high brightness (L* = 50.1) and greenness (a* = −20.8), and these values were as high as those of the conventional green pigments such as chromium oxide and cobalt green. Therefore, the (La0.94Ca0.06)Sr2(Al0.97Mn0.03)O5 pigment is a potential candidate for a novel environmentally friendly inorganic green pigment.
      Citation: Ceramics
      PubDate: 2023-11-22
      DOI: 10.3390/ceramics6040138
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2282-2294: Hydroxyapatite-Resin Composites
           Produced by Vat Photopolymerization and Post-Processing via In Situ
           Hydrolysis of Alpha Tricalcium Phosphate

    • Authors: Carolina Oliver-Urrutia, Lenka Drotárová, Sebastián Gascón-Pérez, Karel Slámečka, Simona Ravaszová, Ladislav Čelko, Edgar B. Montufar
      First page: 2282
      Abstract: Vat photopolymerization is an additive manufacturing technique that utilizes photosensitive resins to fabricate 3D polymeric objects with high precision. However, these objects often lack mechanical strength. This study investigated the strengthening of a resin based on epoxidized soybean oil acrylate, specifically designed for vat photopolymerization, by the in situ formation of hydroxyapatite nanocrystals. First, a stable alpha tricalcium phosphate (α-TCP)-resin feedstock mixture was developed (~30 vol.% α-TCP), which proved suitable for fabricating monoliths as well as complex triply periodic minimal surface (gyroid, diamond, and Schwarz) porous structures through vat photopolymerization. The results demonstrated that the incorporation of α-TCP particles led to a significant mechanical improvement of the resin. Second, post-printing hydrothermal treatments were utilized to transform the α-TCP particles into hydroxyapatite crystals within the resin. It was observed that the space between hydroxyapatite crystals within the composites was occupied by the cured resin, resulting in a more compact, stronger, and mechanically more reliable material than the porous hydroxyapatite produced by the hydrolysis of α-TCP mixed with water. Moreover, water absorption during the hydrothermal treatments caused the plasticization of the cured resin. As a consequence, the hydroxyapatite-resin composites displayed slightly lower mechanical properties compared to the as-printed α-TCP-resin composite.
      Citation: Ceramics
      PubDate: 2023-11-24
      DOI: 10.3390/ceramics6040139
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 2295-2306: Features of Structures and Ionic
           Conductivity of Na3Fe2(PO4)3 Polycrystals Obtained by Solid Phase and Melt

    • Authors: A. S. Nogai, A. A. Nogai, D. E. Uskenbaev, A. B. Utegulov, E. A. Nogai, D. D. Toleugulov
      First page: 2295
      Abstract: This article investigates the structures and conductive properties of polycrystals of Na3Fe2(PO4)3 obtained by solid-state and melt synthesis methods using concentrated optical radiation. It has been established that in the melt synthesis method, the material is synthesized under significantly non-equilibrium thermodynamic conditions, leading to the creation of deformations in the sample, which contribute to the enhancement of ionic conductivity. Additionally, the synthesis duration is reduced by half. Through a comparative assessment of the structural parameters and conductive properties of these materials, it is demonstrated that polycrystals obtained by the melt method exhibit better texture and higher ionic conductivity. The occurrence of deformations during the synthesis of α-Na3Fe2(PO4)3 under high temperature-gradient conditions indicates the elasticity of the crystalline framework {[Fe2(PO4)]3−}3∞. It is concluded that the non-equilibrium thermodynamic conditions of α-Na3Fe2(PO4)3 synthesis promote the formation of deformations in the crystalline structure of polycrystals, leading to a partial increase in symmetry and ionic conductivity.
      Citation: Ceramics
      PubDate: 2023-11-29
      DOI: 10.3390/ceramics6040140
      Issue No: Vol. 6, No. 4 (2023)
  • Ceramics, Vol. 6, Pages 1302-1313: Fabrication of Segments for ZnO-based
           Tube Ceramic Targets by the Spark Plasma Sintering Method

    • Authors: Akhmed K. Akhmedov, Abil Sh. Asvarov, Soslan Sh. Makhmudov, Vladimir M. Kanevsky
      First page: 1302
      Abstract: In this article, problems associated with the fabrication of ZnO-based ceramics in the form of large-diameter hollow cylinders with a large ratio of height h to wall thickness ∆r (h/∆r ≥ 3) by the spark plasma sintering (SPS) method were studied. The design of the press-form is proposed, which ensures the reduction in temperature gradients along the inner and outer surfaces of the hollow cylindrical sintered body and, as a result, the achievement of a high-density uniformity of the sintered body over its volume. A hollow cylindrical ZnO-based ceramic sample considered as segments of TCO tube targets with outer diameter D = 72 mm, inner diameter d = 47 mm, and height h = 36 mm were fabricated. The sample had a relative density of more than 98.5% of the theoretical density for a given composition with a minimal density inhomogeneity along the height of the sample. The microstructure of the obtained ceramics was studied using the SEM and XRD methods.
      Citation: Ceramics
      PubDate: 2023-06-21
      DOI: 10.3390/ceramics6030080
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1314-1329: Barium Silicate Glasses and
           Glass–Ceramic Seals for YSZ-Based Electrochemical Devices

    • Authors: Alyona Vepreva, Dmitry Dubovtsev, Daria Krainova, Yulia Chetvertnykh, Semyon Belyakov, Nailya Saetova, Anton Kuzmin
      First page: 1314
      Abstract: The effect of partial SiO2 substitution with Al2O3 and B2O3 on the thermal properties and crystallization of glass sealants in the (50 − x)SiO2–30BaO–20MgO–xAl2O3(B2O3) (wt %) system is studied. It is established that the coefficient of thermal expansion of all obtained glasses lies within a range of 8.2–9.9 × 10−6 K−1. Alumina-doped glasses crystallize after quenching, while samples containing boron oxide are completely amorphous. Magnesium silicates are formed in all glasses after exposure at 1000 °C for 125 h. After 500 h of exposure, a noticeable diffusion of zirconium ions is observed from the YSZ electrolyte to the glass sealant volume, resulting in the formation of the BaZrSi3O9 compound. The crystallization and products of interaction between YSZ ceramics and boron-containing sealants have no significant effects on the adhesion and properties of glass sealants, which makes them promising for applications in electrochemical devices.
      Citation: Ceramics
      PubDate: 2023-06-22
      DOI: 10.3390/ceramics6030081
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1330-1347: A Review of Zirconolite Solid Solution
           Regimes for Plutonium and Candidate Neutron Absorbing Additives

    • Authors: Lewis R. Blackburn, Claire L. Corkhill, Neil C. Hyatt
      First page: 1330
      Abstract: Should the decision be made to immobilise the UK Pu inventory through a campaign of Hot Isostatic Pressing (HIP) in a zirconolite matrix, prior to placement in a geological disposal facility (GDF), a suite of disposability criteria must be satisfied. A GDF safety case should be able to demonstrate that post-closure criticality is not a significant concern by demonstrating that such an event would have a low likelihood of occurring and low consequence if it were to occur. In the case of ceramic wasteforms, an effective means of criticality control may be the co-incorporation of a requisite quantity of a suitable neutron absorbing additive, either through co-immobilisation within the host structure or the encapsulation of discrete particles within the grain structure. Following an initial screening of a range of potential neutron absorbing additives, a literature-based assessment of the solid solution limits of a number of potential additives (Gd, Hf, Sm, In, Cd, B) in the candidate zirconolite (CaZrTi2O7) wasteform is presented. Key areas of research that are in need of development to further support the safety case for nuclearised HIP for Pu inventories are discussed.
      Citation: Ceramics
      PubDate: 2023-06-22
      DOI: 10.3390/ceramics6030082
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1348-1364: New Glasses in the
           PbCl2–PbO–B2O3 System: Structure and Optical Properties

    • Authors: Dmitry Butenkov, Anna Bakaeva, Kristina Runina, Igor Krol, Maria Uslamina, Aleksandr Pynenkov, Olga Petrova, Igor Avetissov
      First page: 1348
      Abstract: New oxychloride lead borate glasses in the xPbCl2–(50-0.5x)PbO–(50-0.5x)B2O3 system were synthesized with a maximum lead chloride content of 40 mol%. The characteristic temperatures and mechanical and optical properties were studied. The incorporation of lead chloride led to a significant expansion of the transparency range in the UV (up to 355 nm) and IR regions (up to 4710 nm). Decreases in the Vickers hardness, density, and glass transition temperature were the consequences of a change in the structure. The studied glasses are promising materials for photonics and IR optics. The structure of the PbCl2–PbO–B2O3 system was analyzed in detail using vibrational spectroscopy and X-ray diffraction.
      Citation: Ceramics
      PubDate: 2023-06-27
      DOI: 10.3390/ceramics6030083
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1365-1383: Fiber-Reinforced Clay: An Exploratory
           Study on Automated Thread Insertion for Enhanced Structural Integrity in

    • Authors: Hui-Qin Yang, Christina Klug, Thomas H. Schmitz
      First page: 1365
      Abstract: This exploratory study examines the potential of combining clay and natural fiber material in liquid deposition modeling (LDM) to enhance the structural integrity of the soft-bodied print during the additive manufacturing (AM) process. For this purpose, a custom extruder module and a support structure have been developed as novel additions to the delta 3D printer that allows for automated fiber thread insertion into the deposit clay body and stabilize the 3D print during drying. This study explores material compatibility and durability in the liquid state and the material strength of the sintered ceramic body after pyrolysis of the natural fibers. The findings demonstrate the feasibility of an automated process for thread insertion and tensioning control to stabilize and control the 3D print until drying and showcase the versatile design possibilities of this method. The study may serve as a baseline for future research on fiber-reinforced clay printing in the construction industry and related disciplines.
      Citation: Ceramics
      PubDate: 2023-06-28
      DOI: 10.3390/ceramics6030084
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1384-1396: An Anode-Supported Solid Oxide Fuel
           Cell (SOFC) Half-Cell Fabricated by Hybrid 3D Inkjet Printing and Laser

    • Authors: Inna Malbakhova, Artem Bagishev, Alexander Vorobyev, Tatiana Borisenko, Olga Logutenko, Elizaveta Lapushkina, Alexander Titkov
      First page: 1384
      Abstract: A NiO-10YSZ/10YSZ half-cell for anode-supported solid oxide fuel cells (SOFCs) was fabricated using 3D inkjet printing and layer-by-layer laser treatment of printing compositions followed by thermal sintering by a co-firing method. The optimal granulometric composition and rheological characteristics of the printing compositions to fabricate the NiO-10YSZ (60:40 wt.%) anode support, NiO-10YSZ (40:60 wt.%) anode functional layer (AFL), and 10YSZ electrolyte were determined. Effects of the pore former and laser post-treatment on the morphology of the as-prepared anodes for the manufacture of SOFC anode supports were studied, and the optimum laser exposure for hybrid 3D printing was determined. A mechanism of influence of the exposure of laser post-treatment on the morphology of the NiO-10YSZ anode supports has been proposed. The mass content of 10YSZ and the number of layers were shown to affect the surface microstructure and the thickness of the thin-film electrolytes deposited on the surface of the anode supports. The hybrid inkjet 3D printing offers great opportunities as it allows a one-pot procedure to fabricate a NiO-10YSZ/10YSZ SOFC half-cell for SOFC anode supports.
      Citation: Ceramics
      PubDate: 2023-06-30
      DOI: 10.3390/ceramics6030085
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1397-1414: Carbonate-Hydroxyapatite Cement: The
           Effect of Composition on Solubility In Vitro and Resorption In Vivo

    • Authors: Yulia Lukina, Leonid Bionyshev-Abramov, Sergey Kotov, Natalya Serejnikova, Dmitriiy Smolentsev, Sergey Sivkov
      First page: 1397
      Abstract: The rate of resorption of calcium phosphate self-hardening materials for bone regeneration can be changed by changing the phase composition. The Ca3(PO4)2/CaCO3/Ca(H2PO4)2·H2O/Na2HPO4·12H2O system is important for the synthesis of self-curing bioactive materials with variable resorption rates by changing the ratios of the initial components. Cement compositions in twelve figurative points of a four-component composition diagram at a fixed content in the α-Ca3(PO4)2 system were studied with XRD, FTIR, SEM, calorimetric, and volumetric methods to obtain an idea of the effect of composition on solubility in vitro and resorption in vivo. It was found that the presence of the highly resorbable phase of dicalcium phosphate dihydrate in cement and the substitution of phosphate ions with the carbonate ions of hydroxyapatite increased solubility in vitro and resorption in vivo. The obtained results confirm the possibility of changing the solubility of a final product in the Ca3(PO4)2/CaCO3/Ca(H2PO4)2·H2O/Na2HPO4·12H2O system by changing the ratio of the initial components.
      Citation: Ceramics
      PubDate: 2023-07-03
      DOI: 10.3390/ceramics6030086
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1415-1433: Application the Ion Beam Sputtering
           Deposition Technique for the Development of Spin-Wave Structures on
           Ferroelectric Substrates

    • Authors: Sergei A. Sharko, Aleksandra I. Serokurova, Nikolay N. Novitskii, Valerii A. Ketsko, Alexandre I. Stognij
      First page: 1415
      Abstract: The microwave properties of structures in the form of the 2 μm iron-yttrium garnet (YIG) films, grown by the ion beam sputtering deposition method on epitaxially mismatched substrates of ferroelectric ceramics based on lead zirconate titanate (PZT, PbZr0.45Ti0.55O3), are discussed. The obtained structures were formed and pre-smoothed by the ion beam planarization substrates with the use of an anti-diffusion layer of titanium dioxide TiO2. The atomic force microscopy showed that the planarization of the substrates allows for reaching a nanoscale level of roughness (up to 10 nm). The presence of smooth plane–parallel interfaces of YIG/TiO2 and TiO2/PZT is evidenced by scanning electron microscopy performed in focused gallium ion beams. Ferromagnetic resonance spectroscopy revealed a broadening in the absorption line of the ferrite garnet layers in the resonance ≈ 100 Oe. This broadening is associated with the presence of defects caused by the of the ceramic substrate non-ideality. The estimated damping coefficient of spin waves turned out to be ~10−3, which is two orders of magnitude higher than in an ideal YIG single crystal. The YIG/TiO2/PZT structures obtained can be used for the study of spin waves.
      Citation: Ceramics
      PubDate: 2023-07-05
      DOI: 10.3390/ceramics6030087
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1434-1448: Materials in the CaO-K2O-SO3-H2O System
           Based on Powder Mixtures including Calciolangbeinite K2Ca2(SO4)3 and
           Calcium Sulfate Anhydrite CaSO4

    • Authors: Alexander I. Kuznetsov, Tatiana V. Safronova, Tatiana B. Shatalova, Yaroslav Y. Filippov, Leonid A. Vaymugin, Vyacheslav S. Vlasenko, Maxim S. Likhanov
      First page: 1434
      Abstract: Materials (cement stone samples) in the CaO-K2O-SO3-H2O system with the target phase compositions, including syngenite K2Ca(SO4)2·H2O and calcium sulfate dihydrate CaSO4·2H2O, were prepared from powder mixtures of calcium sulfate anhydrite CaSO4, and/or calciolangbeinite K2Ca2(SO4)3, and potassium sulfate K2SO4 via hydration reactions at a water/powder ratio within an interval of 0.5–0.9. It was revealed that samples with contents of 25, 50, 75 and 100 mol% of syngenite K2Ca(SO4)2·H2O demonstrated a nonlinear dependence of their respective microstructures on their phase compositions. The microstructures of samples with phase compositions of 25 and 75 mol% of syngenite K2Ca(SO4)2·H2O consisted of pillar crystals. The microstructures of samples with phase compositions of 50 and 100 mol% of syngenite K2Ca(SO4)2·H2O consisted of plate crystals. An explanation of microstructure formation was set forth, taking into account equilibria of the dissolution–crystallization processes during cement stone formation. Materials obtained in the CaO-K2O-SO3-H2O system consisting of biocompatible and resorbable (soluble in water) phases can be recommended for testing as potential substances for bone defect treatments.
      Citation: Ceramics
      PubDate: 2023-07-05
      DOI: 10.3390/ceramics6030088
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1449-1466: Optimizing Building Thermal Insulation:
           The Impact of Brick Geometry and Thermal Coefficient on Energy Efficiency
           and Comfort

    • Authors: Ioannis Makrygiannis, Konstantinos Karalis
      First page: 1449
      Abstract: The thermal insulation properties of building walls are critical to the overall energy efficiency and comfort of a building. One important factor that can affect these properties is the type of bricks used in construction. Bricks can vary in their geometry and thermal coefficient, which can impact their ability to transfer heat through the wall. The geometry of a brick can affect its thermal properties by altering the amount of air trapped within it and the surface area available for heat transfer. Hollow bricks or those with complex geometries may have lower thermal conductivity than regular solid bricks due to the air pockets trapped within them. Conversely, larger surface areas on the exterior of the brick can increase heat transfer. The thermal coefficient of clay, a common material used in brick production, is another important factor. Clay has relatively low thermal conductivity, meaning it is a poor conductor of heat. However, the quality of the clay, as well as the firing temperature and duration used in brick production, can impact its thermal coefficient. Higher firing temperatures and longer firing times can result in a more compact and dense clay brick, which can improve its thermal properties. In summary, the thermal insulation properties of building walls can be significantly affected by the type of bricks used in their construction. It is important to consider the geometry and thermal coefficient of the bricks when designing a building to achieve the desired level of thermal insulation. By selecting bricks with appropriate properties, designers can help to improve the energy efficiency and comfort of the building while reducing its environmental impact.
      Citation: Ceramics
      PubDate: 2023-07-05
      DOI: 10.3390/ceramics6030089
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1467-1477: Magnesium Oxide and Magnesium Fluoride
           Nanopowders Produced in a Diffuse Nanosecond Discharge in Argon

    • Authors: Dmitry Beloplotov, Konstantin Savkin, Viktor Semin, Dmitry Sorokin
      First page: 1467
      Abstract: The synthesis of the nanopowders of magnesium oxide and magnesium fluoride during the operation of a repetitive diffuse nanosecond discharge in argon at various pressures was performed. Nanosecond voltage pulses with an amplitude of −70 kV, a rise time of 0.7 ns, and a duration of 0.7 ns were applied across a point-to-plane gap of 2 mm in length. The pulse repetition rate was 60 Hz. The high-voltage pointed electrode was made of magnesium. A diffuse discharge cold plasma was formed under these conditions. Nanoparticles were produced as a result of an explosion of microprotrusions on the surface of the magnesium electrode duo to a high current density. Lines of magnesium atoms and ions were observed in the emission optical spectrum. Under the actions of the gas dynamics processes caused by the plasma channel expansion during the interpulse period, nanoparticles were deposited onto the surface of the grounded plane electrode and the side wall of the gas discharge chamber. The morphology, elemental, and phase composition of the powders were studied using transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS).
      Citation: Ceramics
      PubDate: 2023-07-06
      DOI: 10.3390/ceramics6030090
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1478-1489: Effect of a Phosphorus Additive on
           Luminescent and Scintillation Properties of Ceramics GYAGG:Ce

    • Authors: Lydia V. Ermakova, Valentina G. Smyslova, Valery V. Dubov, Daria E. Kuznetsova, Maria S. Malozovskaya, Rasim R. Saifutyarov, Petr V. Karpyuk, Petr S. Sokolov, Ilia Yu. Komendo, Aliaksei G. Bondarau, Vitaly A. Mechinsky, Mikhail V. Korzhik
      First page: 1478
      Abstract: The production of scintillating ceramics can require the utilization of the phosphorus compounds at certain stages of 3D-printing, such as vat polymerization, applied for the formation of green bodies before sintering. The effect of phosphorus additive on the microstructure, optical, and scintillation parameters of Gd1.494Y1.494 Ce0.012Al2Ga3O12 (GYAGG:Ce) ceramics obtained by pressureless sintering at 1650 °C in an oxygen atmosphere was investigated for the first time. Phosphorus was introduced in the form of NH4H2PO4 into the initial hydroxycarbonate precipitate in a wide concentration range (from 0 to 0.6 wt.%). With increasing of phosphorus concentration, the density and the optical transmittance of garnet ceramics show a decrease, which is caused by an increase in the number of pores and inclusions. The light yield of fast scintillation, which is caused by Ce3+ ions, was found to be affected by the phosphorus additive as well. Moreover, an increase in phosphorescence intensity was recognized.
      Citation: Ceramics
      PubDate: 2023-07-06
      DOI: 10.3390/ceramics6030091
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1490-1507: Phase Transformations upon Formation of
           Transparent Lithium Alumosilicate Glass-Ceramics Nucleated by Yttrium

    • Authors: Olga Dymshits, Anastasia Bachina, Irina Alekseeva, Valery Golubkov, Marina Tsenter, Svetlana Zapalova, Kirill Bogdanov, Dmitry Danilovich, Alexander Zhilin
      First page: 1490
      Abstract: Phase transformations in the lithium aluminosilicate glass nucleated by a mixture of yttrium and niobium oxides and doped with cobalt ions were studied for the development of multifunctional transparent glass-ceramics. Initial glass and glass-ceramics obtained by isothermal heat-treatments at 700–900 °C contain YNbO4 nanocrystals with the distorted tetragonal structure. In samples heated at 1000 °C and above, the monoclinic features are observed. High-temperature X-ray diffraction technique clarifies the mechanism of the monoclinic yttrium orthoniobate formation, which occurs not upon high-temperature heat-treatments above 900 °C but at cooling the glass-ceramics after such heat-treatments, when YNbO4 nanocrystals with tetragonal structure undergo the second-order transformation at ~550 °C. Lithium aluminosilicate solid solutions (ss) with β-quartz structure are the main crystalline phase of glass-ceramics prepared in the temperature range of 800–1000 °C. These structural transformations are confirmed by Raman spectroscopy and illustrated by SEM study. The absorption spectrum of the material changes only with crystallization of the β-quartz ss due to entering the Co2+ ions into this phase mainly in octahedral coordination, substituting for Li+ ions. At the crystallization temperature of 1000 °C, the Co2+ coordination in the β-quartz solid solutions changes to tetrahedral one. Transparent glass-ceramics have a thermal expansion coefficient of about 10 × 10−7 K−1.
      Citation: Ceramics
      PubDate: 2023-07-06
      DOI: 10.3390/ceramics6030092
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1508-1516: A Study of PbF2 Nanoparticles
           Crystallization Mechanism in Mixed Oxyde-Fluoride Glasses

    • Authors: Saule Dyussembekova, Ekaterina Trusova, Sergey Kichanov, Kiril Podbolotov, Denis Kozlenko
      First page: 1508
      Abstract: Samples of nanocrystalline PbF2 glass ceramics were obtained by heat-treating SiO2–GeO2–PbO–PbF2–CdF2 glasses. The Ho2O3 and Tm2O3 doping effects on the structural features of PbF2 nanoparticles were studied using small-angle X-ray scattering and X-ray diffraction methods. The enlargements of the average sizes of nanoparticles and the sizes of local areas of density fluctuations have been found to be correlated with an increase in concentrations of Ho2O3 and Tm2O3 in initial glasses. A variation in the concentrations of Ho2O3 and Tm2O3 does not affect the morphology and fractal dimension of the formed PbF2 nanoparticles.
      Citation: Ceramics
      PubDate: 2023-07-11
      DOI: 10.3390/ceramics6030093
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1517-1530: A Review of Cr2+ or Fe2+ Ion-Doped Zinc
           Sulfide and Zinc Selenide Ceramics as IR Laser Active Media

    • Authors: Natalia Timofeeva, Stanislav Balabanov, Jiang Li
      First page: 1517
      Abstract: Zinc chalcogenides doped with Cr2+ or Fe2+ ions are of considerable interest as active media for IR lasers operating in the 2–5 µm wavelength range. Such lasers are in demand in various fields of medicine, remote sensing and atmospheric monitoring, ranging, optical communication systems, and military applications. In recent years, however, the rate of improvement in the characteristics of zinc chalcogenide laser sources has slowed considerably. Unwanted thermally induced effects, parasitic oscillations, and laser-induced damage of the active element have hindered the scaling of output power and efficiency. However, the physical and chemical properties of the materials leave ample room for further improvements. In particular, the control of the dopant concentration profile in the active element is of great importance. Zero concentration of Cr2+ or Fe2+ ions on the radiation input/output surfaces can significantly increase the laser-induced damage threshold; the designed concentration distribution in the element volume allows regulation of heat dissipation and reduction of parasitic oscillations. The zinc chalcogenide ceramic technology seems to be the most suitable to solve this challenge. This review presents and discusses the state of the art in ZnS and ZnSe optical and laser ceramics and the directions for further development of their technology.
      Citation: Ceramics
      PubDate: 2023-07-11
      DOI: 10.3390/ceramics6030094
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1531-1545: Magnesium Oxide Powder Synthesis in
           Cathodic Arc Discharge Plasma in an Argon Environment at Atmospheric

    • Authors: Dmitry Sorokin, Konstantin Savkin, Dmitry Beloplotov, Viktor Semin, Andrey Kazakov, Alisa Nikonenko, Alexander Cherkasov, Konstantin Shcheglov
      First page: 1531
      Abstract: Discharges with cathode spots can operate in a wide range of gas pressures. Erosion of the cathode material is an inherent property of such discharges. The erosion products are considered to be ionized atoms and electrically neutral microdroplets. In accordance with this concept, a plasma source based on a pulsed cathodic arc discharge in atmospheric-pressure argon with a current of up to 200 A, a pulse duration of 250 μs, and a pulse repetition rate of 10 Hz was implemented. Using this source, the synthesis of magnesium oxide powder was performed. The chemical composition of the erosion products was determined using the TEM/EDS method and the composition of the gas mixture in which the discharge system operated was evaluated by optical spectrometry. It was shown that particles of the synthesized powder have different morphological features, depending on the nature of the electrical erosion of the cathode material. Micron-sized particles are formed due to the removal of microdroplets from liquid–metal craters on the cathode surface at certain plasma pressures. Submicron particles are produced during the agglomeration of atoms originating from the plasma jets flowing out from cathode spots. These atoms are magnesium ions that are neutralized by collisions with gas particles. The advantages and disadvantages of this synthesis method are discussed in this paper. The reference methods for the powder synthesis of magnesium oxide are compared. The prospects of the studied method from the point of view of its application for obtaining ceramic materials are also evaluated.
      Citation: Ceramics
      PubDate: 2023-07-11
      DOI: 10.3390/ceramics6030095
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1546-1558: Formation and Photophysical Properties
           of Silver Clusters in Bulk of Photo-Thermo-Refractive Glass

    • Authors: Leonid Yu. Mironov, Dmitriy V. Marasanov, Mariia D. Sannikova, Ksenia S. Zyryanova, Artem A. Slobozhaninov, Ilya E. Kolesnikov
      First page: 1546
      Abstract: The bright luminescence of silver clusters in glass have potential applications in solid-state lighting, optical memory, and spectral converters. In this work, luminescent silver clusters were formed in the bulk of photo-thermo-refractive glass (15Na2O-5ZnO-2.9Al2O3-70.3SiO2-6.5F, mol.%) doped with different Ag2O concentrations from 0.01 to 0.05 mol.%. The spontaneous formation of plasmonic nanoparticles during glass synthesis was observed at 0.05 mol.% of Ag2O in the glass composition, limiting the silver concentration range for cluster formation. The luminescence of silver clusters was characterized by steady-state and time-resolved spectroscopy techniques. The rate constants of fluorescence, phosphorescence, intersystem crossing, and nonradiative deactivation were estimated on the basis of an experimental study. A comparison of the results obtained for the photophysical properties of luminescent silver clusters formed in the ion-exchanged layers of photo-thermo-refractive glass is provided.
      Citation: Ceramics
      PubDate: 2023-07-13
      DOI: 10.3390/ceramics6030096
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1559-1572: Bismuth-Germanate Glasses: Synthesis,
           Structure, Luminescence, and Crystallization

    • Authors: Ksenia Serkina, Irina Stepanova, Aleksandr Pynenkov, Maria Uslamina, Konstantin Nishchev, Kirill Boldyrev, Roman Avetisov, Igor Avetissov
      First page: 1559
      Abstract: Bismuth-germanate glasses, which are well known as a promising active medium for broadband near-infrared spectral range fiber lasers and as an initial matrix for nonlinear optical glass ceramics, have been synthesized in a 5–50 mol% Bi2O3 wide concentration range. Their structural and physical characteristics were studied by Raman and FT-IR spectroscopy, differential scanning calorimetry, X-ray diffraction, optical, and luminescence methods. It has been found that the main structural units of glasses are [BiO6] and [GeO4]. The growth in bismuth oxide content resulted in an increase in density and refractive index. The spectral and luminescent properties of glasses strongly depended on the amount of bismuth active centers. The maximum intensity of IR luminescence has been achieved for the 5Bi2O3-95GeO2 sample. The heat treatment of glasses resulted in the formation of several crystalline phases, the structure and amount of which depended on the initial glass composition. The main phases were non-linear Bi2GeO5 and scintillating Bi4Ge3O12. Comparing with the previous papers dealing with bismuth and germanium oxide-based glasses, we enlarge the range of Bi2O3 concentration up to 50 mol% and decrease the synthesis temperature from 1300 to 1100 °C.
      Citation: Ceramics
      PubDate: 2023-07-13
      DOI: 10.3390/ceramics6030097
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1573-1622: Zirconolite Matrices for the
           Immobilization of REE–Actinide Wastes

    • Authors: Sergey V. Yudintsev, Maximilian S. Nickolsky, Michael I. Ojovan, Olga I. Stefanovsky, Victor I. Malkovsky, Amina S. Ulanova, Lewis R. Blackburn
      First page: 1573
      Abstract: The structural and chemical properties of zirconolite (ideally CaZrTi2O7) as a host phase for separated REE–actinide-rich wastes are considered. Detailed analysis of both natural and synthetic zirconolite-structured phases confirms that a selection of zirconolite polytype structures may be obtained, determined by the provenance, crystal chemistry, and/or synthesis route. The production of zirconolite ceramic and glass–ceramic composites at an industrial scale appears most feasible by cold pressing and sintering (CPS), pressure-assisted sintering techniques such as hot isostatic pressing (HIP), or a melt crystallization route. Moreover, we discuss the synthesis of zirconolite glass ceramics by the crystallization of B–Si–Ca–Zr–Ti glasses containing actinides in conditions of increased temperatures relevant to deep borehole disposal (DBD).
      Citation: Ceramics
      PubDate: 2023-07-15
      DOI: 10.3390/ceramics6030098
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1623-1631: Phase Composition and Magnetic
           Properties of Nanoparticles with Magnetite–Maghemite Structure

    • Authors: Sergey I. Andronenko, Anton M. Nikolaev, Stanislav M. Suharzhevsky, Alexander A. Sinelnikov, Anastasia S. Kovalenko, Alexandra G. Ivanova, Olga A. Shilova
      First page: 1623
      Abstract: Precipitation of nanopowders with mixed magnetite–maghemite composition was carried out under different conditions and with different separation techniques. The exact character of interactions of different iron oxide phases in the nanopowder was the main object of interest. The obtained nanopowders have spherical particles about 10–20 nm in size. Electron paramagnetic resonance (EPR) study showed that iron ions incorporate fully into magnetite and maghemite structures. The shape of the EPR line points out that single homogenous solid solutions were formed during synthesis. In the studied solid solutions, different ratios of vacancies and Fe2+/Fe3+ ratios were observed but in spite of different synthesis techniques in both cases, there were no additional diamagnetic structural phases presented.
      Citation: Ceramics
      PubDate: 2023-07-18
      DOI: 10.3390/ceramics6030099
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1632-1645: Effect of Diamond Phase Dispersion on
           the Properties of Diamond-SiC-Si Composites

    • Authors: Sergey P. Bogdanov, Andrey S. Dolgin, Sergey N. Perevislov, Nikolay A. Khristyuk, Maxim M. Sychov
      First page: 1632
      Abstract: The research aimed at the composition optimization for diamond-SiC-Si composites. The effect of a porous diamond workpiece was studied on the properties (porosity, density, modulus of elasticity, phase composition) of the product of its siliconization with molten silicon. The lowest porosity and highest modulus of elasticity were observed in the case of using mixed matrices with the maximum size of diamond grains of 250/200 μm for siliconization. The best results in terms of the sound speed (16,600 m/s) and elasticity modulus (860 GPa) were achieved by microwave processing of a composite containing detonation nanodiamonds.
      Citation: Ceramics
      PubDate: 2023-07-28
      DOI: 10.3390/ceramics6030100
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1646-1654: Water-Glass-Assisted Foaming in Foamed
           Glass Production

    • Authors: Sonja Smiljanić, Uroš Hribar, Matjaž Spreitzer, Jakob König
      First page: 1646
      Abstract: The energy efficiency of buildings can be greatly improved by decreasing the energy embodied in installed materials. In this contribution, we investigated the possibility of foaming waste bottle glass in the air atmosphere with the addition of water glass, which would reduce the energy used in the production of foamed glass boards. The results show that with the increased addition of water glass, the crystallinity and the thermal conductivity decrease, however, the remaining crystal content prevents the formation of closed-porous foams. The added water glass only partly protects the carbon from premature oxidation, and the foaming mechanism in the air is different than in the argon atmosphere. The lowest obtained foam density in the air atmosphere is 123 kg m−3, while the lowest thermal conductivity is 53 mW m−1 K−1, with an open porosity of 50% for the sample obtained in the air, containing 12 wt% of water glass, 2 wt% of B2O3, 2 wt% AlPO4 and 2 wt% K3PO4.
      Citation: Ceramics
      PubDate: 2023-08-02
      DOI: 10.3390/ceramics6030101
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1655-1666: Synthesis and Characterization of
           Nd:YAG Ceramics for Laser Applications

    • Authors: Olga Alondra Echartea-Reyes, Gloria Verónica Vázquez-García, José Adalberto Castillo-Robles, Juan López-Hernández, Carlos Adrián Calles-Arriaga, Wilian Jesús Pech-Rodríguez, Enrique Rocha-Rangel
      First page: 1655
      Abstract: Materials known as Nd:YAG are crystalline materials of the cubic system made from the neodymium-doped yttrium aluminum garnet, which, among others, have excellent optical properties. Nd:YAG four-level laser devices are frequently used in both the health and industrial sectors. In this study, a simple and inexpensive alternative to manufacturing Nd:YAG materials through solid state reactions following powder processing routes was proposed. For this, an intense mixture of the precursor materials (Al2O3 and Y2O3) was carried out, followed by the addition of neodymium atoms to improve the optical properties of the resulting material. High-energy mechanical mixing of the precursor powders resulted in submicron particles with good size distributions of the powders. The advance of YAG formation was monitored by intermediate phase formation during heat treatment through interrupted tests at different temperatures and analysis by X-ray diffraction. From this analysis, it was found that reaction for the formation of the desired YAG is completed at 1500 °C. Fourier transform infrared spectroscopy analyses determined the presence of functional groups corresponding to the YAG. Finally, the study employing optical emission spectroscopy showed wavelengths in agreement with those of the electronic structure of the elements of the synthesized Nd:YAG.
      Citation: Ceramics
      PubDate: 2023-08-02
      DOI: 10.3390/ceramics6030102
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1667-1681: Porous Ceramic ZnO Nanopowders:
           Features of Photoluminescence, Adsorption and Photocatalytic Properties

    • Authors: Marianna Gavrilova, Diana Gavrilova, Sergey Evstropiev, Andrey Shelemanov, Igor Bagrov
      First page: 1667
      Abstract: The grainy and porous ZnO powders were synthesized by thermal decomposition of zinc nitrate and polymer-salt method. The comparative study of the crystal structure, morphology, luminescence, adsorptive and photocatalytic properties of ZnO powders was carried out. The addition of PVP in initial aqueous solutions of zinc nitrate determines the remarkable change of powder morphology and decreases the average size of ZnO nanocrystals. Luminescence spectra in the visible spectral range indicate the significant difference of structural defects types in grainy and porous powders. Porous powders demonstrate high ability for singlet oxygen photogeneration and photocatalytic properties. The kinetics of diazo dye adsorption on both powders is described successfully by the kinetic equation of pseudo-second order. Kinetic dependencies of photocatalytic oxidation of Chicago Sky Blue diazo dye using as grain ZnO powder so as porous ZnO powders are described by the Langmuir–Hinshelwood model but process rates are different. Porous ZnO powder demonstrates strong ability for photogeneration of singlet oxygen under visible irradiation and high photocatalytic properties (rate constant 0.042 min−1).
      Citation: Ceramics
      PubDate: 2023-08-02
      DOI: 10.3390/ceramics6030103
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1682-1704: Unlocking the Potential of Biomass Fly
           Ash: Exploring Its Application in Geopolymeric Materials and a Comparative
           Case Study of BFA-Based Geopolymeric Concrete against Conventional

    • Authors: Baturalp Yalcinkaya, Tomas Spirek, Milan Bousa, Petr Louda, Vojtěch Růžek, Cezary Rapiejko, Katarzyna Ewa Buczkowska
      First page: 1682
      Abstract: The production of conventional cement involves high energy consumption and the release of substantial amounts of carbon dioxide (CO2), exacerbating climate change. Additionally, the extraction of raw materials, such as limestone and clay, leads to habitat destruction and biodiversity loss. Geopolymer technology offers a promising alternative to conventional cement by utilizing industrial byproducts and significantly reducing carbon emissions. This paper analyzes the utilization of biomass fly ash (BFA) in the formation of geopolymer concrete and compares its carbon and cost impacts to those of conventional concrete. The previous analysis shows great potential for geopolymers to reduce the climate change impact of cement production. The results of this analysis indicate a significant disparity in the computed financial and sustainability costs associated with geopolymers. Researchers have shown that geopolymers may help mitigate the effects of cement manufacturing on the environment. These geopolymers are predicted to reduce green gas emissions by 40–80%. They also show that those advantages can be realized with the best possible feedstock source and the cheapest possible conveyance. Furthermore, our case study on CO2 emission and cost calculation for BFA-based geopolymer and conventional concrete shows that geopolymer concrete preparation emits 56% less CO2 than conventional concrete while costing 32.4% less per ton.
      Citation: Ceramics
      PubDate: 2023-08-03
      DOI: 10.3390/ceramics6030104
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1705-1734: Zirconia-Based Ceramics Reinforced by
           Carbon Nanotubes: A Review with Emphasis on Mechanical Properties

    • Authors: Soukaina Lamnini, Diego Pugliese, Francesco Baino
      First page: 1705
      Abstract: This review outlines the state of the art, processing techniques, and mechanical testing methods of zirconia (ZrO2)-based composites reinforced by carbon nanotubes (CNTs). The use of CNTs as a secondary phase in a zirconia matrix is motivated by their outstanding crack self-healing ability, the possibility to tailor the desired nano-structural properties, and their exceptional wear behavior. Therefore, a detailed investigation into CNT features has been provided. The debate of using the different Vickers indentation fracture toughness equations to estimate the resistance of crack propagation was critically reviewed according to crack characteristics. Finally, this review particularly highlights the exceptional role of ZrO2-based composites as a promising material owing to their outstanding tribo-mechanical properties.
      Citation: Ceramics
      PubDate: 2023-08-06
      DOI: 10.3390/ceramics6030105
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1735-1748: Structure and Relaxor Behavior of (0.5
           − x)BiFeO3-0.5PbFe0.5Nb0.5O3-xPbTiO3 Ternary Ceramics

    • Authors: Nikita A. Boldyrev, Eugene I. Sitalo, Lidia A. Shilkina, Alexander V. Nazarenko, Andrei D. Ushakov, Vladimir Y. Shur, Larisa A. Reznichenko, Ekaterina V. Glazunova
      First page: 1735
      Abstract: Ceramics of the quasi-binary concentration section (0.1 ≤ x ≤ 0.2, Δx = 0.025) of the ternary solid solution system (0.5 − x)BiFeO3-0.5PbFe0.5Nb0.5O3-xPbTiO3 were prepared by the conventional solid-phase reaction method. An X-ray study at different temperatures revealed that (0.5 − x)BF-0.5PFN-xPT ceramics have a cluster morphology. Clusters have different modulation, crystal lattice symmetry, and chemical composition. The presence of a cluster structure in a solid solution with heterovalent substitution, consisting of regions rich in Ti+4, Nb+5, or Fe3+, has led to the appearance of Maxwell–Wagner polarization in the studied ceramics. The study of the dielectric characteristics revealed the relaxor-like behavior of the studied ceramics. The grain morphology, dielectric, pyroelectric, and piezoelectric properties of the selected solid solutions were investigated. The highest piezoelectric coefficient, d33 = 280 pC/N, was obtained in the 0.3BiFeO3-0.5PbFe0.5Nb0.5O3-0.2PbTiO3 ceramics. Study of the dielectric characteristics of all samples revealed relaxor ferroelectric behavior and a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 140–170 °C.
      Citation: Ceramics
      PubDate: 2023-08-08
      DOI: 10.3390/ceramics6030106
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1749-1764: Geopolymer Antimicrobial and
           Hydrophobic Modifications: A Review

    • Authors: Vojtěch Růžek, Jan Novosád, Katarzyna Ewa Buczkowska
      First page: 1749
      Abstract: The article summarizes the state of the art in increasing antimicrobial activity and hydrophobic properties of geopolymer materials. Geopolymers are inorganic polymers formed by polycondensation of aluminosilicate precursors in an alkaline environment and are considered a viable alternative to ordinary Portland cement-based materials, due to their improved mechanical properties, resistance to chemicals, resistance to high temperature, and lower carbon footprint. Like concrete, they are susceptible to microbially induced deterioration (corrosion), especially in a humid environment, primarily due to surface colonization by sulphur-oxidizing bacteria. This paper reviews various methods for hydrophobic or antimicrobial protection by the method of critical analysis of the literature and the results are discussed, along with potential applications of geopolymers with improved antimicrobial properties. Metal nanoparticles, despite their risks, along with PDMS and epoxy coatings, are the most investigated and effective materials for geopolymer protection. Additionally, future prospects, risks, and challenges for geopolymer research and protection against degradation are presented and discussed.
      Citation: Ceramics
      PubDate: 2023-08-11
      DOI: 10.3390/ceramics6030107
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1765-1787: Alkali-Activated Brick Aggregates as
           Industrial Valorized Wastes: Synthesis and Properties

    • Authors: Abdel Boughriet, Oscar Allahdin, Nicole Poumaye, Gildas Doyemet, Grégory Tricot, Bertrand Revel, Baghdad Ouddane, Michel Wartel
      First page: 1765
      Abstract: In recent works, many industrial by-products were employed as solid precursors for the synthesis of alkali-activated binders and as alternatives to Portland cement for the immobilization of hazardous, toxic and nuclear wastes. Among industrial wastes, alkali-activated brick was found to be an interesting porous composite for removing very toxic heavy metals (Pb2+, Cd2+, Co2+) and radio-nuclides (Sr2+, Cs+, Rb+) from aqueous solutions. The starting material is very attractive due to the presence of metakaolinite as a geo-polymer precursor and silica for increasing material permeability and facilitating water filtration. The alkaline reaction gave rise to geo-polymerization followed by partial zeolitization. Elemental surface micro-analysis was performed by Scanning Electron Microscopy (SEM) equipped with an Energy-Dispersive X-ray Spectrometer (EDS). The formation of crystalline phases was corroborated by X-ray diffraction (XRD) analysis. Information about 29Si, 27Al and 1H nuclei environments in crystallized and amorphous aluminosilicates was obtained by 29Si, 27Al and 1H MAS NMR. 27Al–1H dipolar-mediated correlations were investigated by employing dipolar hetero-nuclear multiple quantum coherence (D-HMQC) NMR, highlighting Al–O–H bonds in bridging hydroxyl groups (Si–OH–Al) that are at the origin of adsorptive properties. Aqueous structural stability and cationic immobilization characteristics before and after material calcination were investigated from acid-leaching experiments.
      Citation: Ceramics
      PubDate: 2023-08-14
      DOI: 10.3390/ceramics6030108
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1788-1798: Influence of Alkali Metal Ions on the
           Structural and Spectroscopic Properties of Sm3+-Doped Silicate Glasses

    • Authors: Israel R. Montoya Matos
      First page: 1788
      Abstract: In the present work, the influence of alkali ions (Li, Na, K) on the structural and spectroscopic properties of silica glasses doped with Sm3+ was investigated. Infrared and Raman spectroscopy techniques were used to investigate the structural properties of the alkali silicate glasses. The optical absorption showed bands characteristic of Sm3+ ions in alkali silicate glasses, and this was investigated. The Judd–Ofelt theory was applied to evaluate the phenomenological intensity parameters (Ω2, Ω4, and Ω6) of the optical absorption measurements. The multi-channel visible and near infrared emission transitions originating from the 4G5/2-emitting state of the Sm3+ in alkali silicate glasses with a maximum phonon energy of ~1050 cm−1 were investigated. From the evaluated Judd–Ofelt parameters, radiative parameters such as spontaneous emission probabilities, radiative lifetimes, branching ratios, and stimulated emission cross-sections were calculated. The recorded luminescence spectra regions revealed intense green, orange, red, and near-infrared emission bands, providing new traces for developing tunable laser and optoelectronic devices.
      Citation: Ceramics
      PubDate: 2023-08-21
      DOI: 10.3390/ceramics6030109
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1799-1825: Nutrient-Doped Hydroxyapatite:
           Structure, Synthesis and Properties

    • Authors: Mohamed Ammar, Sherif Ashraf, Jonas Baltrusaitis
      First page: 1799
      Abstract: Complex inorganic powders based on calcium phosphates have found a plethora of practical applications. Of particular interest are the CaO-P2O5 system-based multi-component material powders and granules as the source of major- and micronutrients for the plants. The emerging strategy is to use nano fertilizers based on hydroxyapatite (HAP) for phosphorus and other nutrient delivery. The doping of micronutrients into HAP structure presents an interesting challenge in obtaining specific phase compositions of these calcium phosphates. Various techniques, including mechanochemical synthesis, have been employed to fabricate doped HAP. Mechanochemical synthesis is of particular interest in this review since it presents a relatively simple, scalable, and cost-effective method of calcium phosphate powder processing. The method involves the use of mechanical force to promote chemical reactions and create nanometric powders. This technique has been successfully applied to produce HAP nanoparticles alone, and HAP doped with other elements, such as zinc and magnesium. Nanofertilizers developed through mechanochemical synthesis can offer several advantages over conventional fertilizers. Their nanoscale size allows for rapid absorption and controlled release of nutrients, which leads to improved nutrient uptake efficiency by plants. Furthermore, the tailored properties of HAP-based nano fertilizers, such as controlled porosity and degradation levels, contribute to their effectiveness in providing plant nutrition.
      Citation: Ceramics
      PubDate: 2023-08-22
      DOI: 10.3390/ceramics6030110
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1826-1839: An Investigation of Iodovanadinite
           Wasteforms for the Immobilisation of Radio-Iodine and Technetium

    • Authors: Daniel J. Bailey, Erik V. Johnstone, Martin C. Stennett, Claire L. Corkhill, Neil C. Hyatt
      First page: 1826
      Abstract: 99Tc and 129I are two long-lived, highly soluble and mobile fission products that pose a long-term hazard. A proposed wasteform for the disposal of radio-iodine is iodovanadinite (Pb5(VO4)3I), an apatite-structured vanadate. In this investigation, a suite of potential iodovanadinite wasteforms designed for the co-disposal of Tc and I or the sole disposal of I were synthesised via hot isostatic pressing (with Mo as a surrogate for Tc). It was found that direct synthesis from oxide and iodide precursors was possible using hot isostatic pressing (HIPing). Increasing overpressure during HIPing was found to improve the density of the final product. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses indicated that the use of AgI as the source of iodine affected the formation of the target iodovanadinite phase and produced unfavourable phase assemblages. Here, we report the direct synthesis of Pb5(VO4)3I in a single step by hot isostatic pressing.
      Citation: Ceramics
      PubDate: 2023-08-24
      DOI: 10.3390/ceramics6030111
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1840-1849: Phase Formation and Properties of
           Multicomponent Solid Solutions Based on Ba(Ti, Zr)O3 and AgNbO3 for
           Environmentally Friendly High-Efficiency Energy Storage

    • Authors: Dmitry V. Volkov, Ekaterina V. Glazunova, Lydia A. Shilkina, Aleksandr V. Nazarenko, Aleksey A. Pavelko, Vyacheslav A. Bobylev, Larisa A. Reznichenko, Ilya A. Verbenko
      First page: 1840
      Abstract: This paper investigates the processes of phase formation of solid solutions of (1 − x)BaTi0.85Zr0.15O3 − xAgNbO3 where x = 0, 0.03, 0.06, 0.09. The optimal temperatures of synthesis and sintering are determined. From the results of X-ray diffraction analysis, it follows that all solid solutions have a perovskite-type structure. Analysis of the microstructure showed that the average grain size decreases at concentrations x = 0.03 and 0.06. Correlations between the cationic composition and dielectric characteristics of the studied solid solutions have been established. The values of the total stored energy and efficiency are determined. The maximum stored energy was found for a solid solution with x = 0.03 and amounted to 0.074 J∙cm−3 with an efficiency of 76.5%.
      Citation: Ceramics
      PubDate: 2023-08-26
      DOI: 10.3390/ceramics6030112
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1850-1860: Anodic Performance of Ni–BCZY and
           Ni–BCZY–GDC Films on BCZY Electrolytes

    • Authors: Yoshiteru Itagaki, Yota Kumamoto, Susumu Okayama, Hiromichi Aono
      First page: 1850
      Abstract: Cermet films consisting of Ni, BaCe0.4Zr0.4Y0.2O3−δ (BCZY), and Gd0.1Ce0.9Ox (GDC), specifically, 60 wt%Ni–BCZY, 60 wt%Ni–BCZY–GDC, and 60 wt%Ni–GDC, were formed on BCZY electrolyte supports as anodes of proton ceramic fuel cells (PCFCs). The Ni grain size in these films after sintering at 1450 °C was around 2 μm. The GDC addition did not affect the Ni grain size in the case of the BCZY matrix. The anodic properties greatly depended on the oxide phase composition and worsened with increasing the GDC content. This probably occurred because of the addition of GDC, which has low proton conductivity and inhibited the proton conduction path of BCZY, reducing three-phase boundaries in the anode bulk. Since BCZY has a lower grain growth rate during sintering than BaCe0.8Y0.2O3−δ, the Ni grain growth was likely suppressed by the surrounding Ni grains containing small BCZY grains.
      Citation: Ceramics
      PubDate: 2023-09-05
      DOI: 10.3390/ceramics6030113
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1861-1878: Developing Geopolymer Concrete by Using
           Ferronickel Slag and Ground-Granulated Blast-Furnace Slag

    • Authors: Quang Dieu Nguyen, Arnaud Castel
      First page: 1861
      Abstract: Geopolymer concrete is gaining recognition as an environmentally friendly alternative to traditional cement-based materials, offering potential solutions for reducing the carbon emissions of the construction industry. This study aims to develop GGBFS–FNS geopolymers utilising ferronickel slag (FNS) and ground-granulated blast-furnace slag (GGBFS). Ground FNS (GFNS) is a potential candidate for replacing fly ash in geopolymers. This research aims to develop for the first time a GGBFS–FNS alkali-activated concrete. Numerous trials were conducted including different GGBFS–FNS blend percentages, several chemical admixtures and varying activator concentrations to develop the optimal binder mix composition. The effects of different chemical admixtures on the properties of geopolymer pastes, mortars, and concretes were investigated. The study evaluated setting time, compressive strength, shrinkage, and physical and durability properties. The results indicate that conventional admixtures have limited impact on the setting time, while increasing the water/solid ratio and decreasing the GGBFS content could extend the initial and final setting times. The presence of FNS aggregate could improve the compressive strength of geopolymer mortars. The water absorber admixture was highly effective in reducing shrinkage and increasing chloride diffusion resistance. The geopolymer mix containing 50 wt.% GFNS and 50 wt.% GGBFS with the presence of the water absorber admixture presented high chloride diffusion resistance, non-reactivity to the alkali–silica reaction and high sulphate resistance. Overall, the GGBFS–FNS geopolymers exhibited promising potential for engineering applications as an environmentally friendly material, particularly in aggressive environments.
      Citation: Ceramics
      PubDate: 2023-09-06
      DOI: 10.3390/ceramics6030114
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1879-1893: Analytical Model of Deformation of a
           Functionally Graded Ceramic Coating under Local Load

    • Authors: Ivan Shatskyi, Mykola Makoviichuk, Liubomyr Ropyak, Andrii Velychkovych
      First page: 1879
      Abstract: In this article, an analytical approach to the study of the behavior of functionally graded FG coatings under local load is developed. The method is suitable for coatings with a specific structure. We consider that the coating can be conditionally divided into two zones: a relatively rigid outer and a relatively compliant inner. The outer layer is modeled by a non-homogeneous plate that bends. We submit the inner substrate to the hypothesis of a non-homogeneous thin Winkler layer. The solution of the formulated boundary value problem is constructed in analytical form. Simulation examples for FG aluminum oxide coatings grown from aluminum sprayed on steel and from compact alloy D16T are considered. The distributions of equivalent stresses, safety factors and normalized equivalent stresses in the coatings are studied. It is noted that in a heterogeneous material, the location of the minimum of the safety factor does not always coincide with the location of the maximum of the equivalent stress.
      Citation: Ceramics
      PubDate: 2023-09-07
      DOI: 10.3390/ceramics6030115
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1894-1899: Metal Halide Perovskite Light-Emitting
           Transistor with Tunable Emission Based on Electrically Doped Semiconductor
           Nanocrystal-Based Microcavities

    • Authors: Francesco Scotognella
      First page: 1894
      Abstract: Electroluminescence of metal halide perovskites has been widely reported via the fabrication and optimization of light-emitting diodes and light-emitting transistors. Light-emitting transistors are particularly interesting owing to the additional control of the gate voltage on the electroluminescence. In this work, the design of a microcavity, with a defect mode that can be tuned with an applied voltage, integrated with a metal halide light-emitting transistor is shown. The optical properties of the device have been simulated with the transfer matrix method, considering the wavelength-dependent refractive indexes of all the employed materials. The tunability of the microcavity has been obtained via the employment of doped semiconductor nanocrystalline films, which show a tunable plasma frequency and, thus, a tunable refractive index as a function of the applied voltage. Consequently, the tunability of the electroluminescence of the metal halide perovskite light-emitting transistor has been demonstrated.
      Citation: Ceramics
      PubDate: 2023-09-11
      DOI: 10.3390/ceramics6030116
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 1900-1912: Compositionally Disordered Ceramic
           (Gd,Y,Tb,Ce)3Al2Ga3O12 Phosphor for an Effective Conversion of
           Isotopes’ Ionizing Radiation to Light

    • Authors: Mikhail V. Korzhik, Petr V. Karpyuk, Aliaksei G. Bondarau, Daria E. Lelecova, Vitaly A. Mechinsky, Vladimir Pustovarov, Vasilii Retivov, Valentina G. Smyslova, Dmitry Tavrunov, Denis N. Yanushevich
      First page: 1900
      Abstract: Compositionally disordered crystalline material (Gd,Y,Tb,Ce)3Al2Ga3O12 was demonstrated to be a highly effective converter of corpuscular ionizing radiation into light. The material was found to be radiation-tolerant to an intense 10 MeV electron beam and had a low temperature dependence on light yield. These findings open an opportunity to utilize the developed material to create long-living, high-flux sources of optical photons under the irradiation of isotope sources. Besides the purposes of the measurement of ionizing radiation by the scintillation method in a harsh irradiation environment, this puts forward the exploiting of the developed material for indirect isotope voltaic batteries and the consideration of a photon engine for travel beyond the solar system, where solar wind force becomes negligible.
      Citation: Ceramics
      PubDate: 2023-09-21
      DOI: 10.3390/ceramics6030117
      Issue No: Vol. 6, No. 3 (2023)
  • Ceramics, Vol. 6, Pages 798-817: Study of the Phase Formation Processes
           and Their Influence on the Change in the Optical and Shielding
           Characteristics of 0.25ZnO–0.25Al2O3–0.25WO3–0.25Bi2O3

    • Authors: Aibek S. Seitbayev, Artem L. Kozlovskiy, Daryn B. Borgekov, Maxim V. Zdorovets
      First page: 798
      Abstract: The phase formation processes in 0.25ZnO–0.25Al2O3–0.25WO3–0.25Bi2O3 ceramics with variation in the thermal annealing temperature were evaluated in this study. According to the obtained data on the phase composition dependent on the annealing temperature, the phase transformation dynamics, which can be written in the form of ZnO/Bi2O3/WO3/Al2O3 → ZnBi38O60/ZnO/Bi2WO6/WO3 → Bi2Al4O9/ZnBi38O60/Bi2WO6/ZnO/WO3 → ZnWO4/Bi2WO6/ZnAl2O4/ZnO → ZnWO4/Bi2WO6/ZnAl2O4 → Bi2WO6/ZnWO4/ZnAl2O4 → ZnAl2O4/Bi2WO6/Bi2W2O9, were established. It has been found that the formation of phases of complex oxides of the ZnWO4, Bi2WO6 and Bi2W2O9 types in the composition of ceramics leads to an increase in the density of ceramics up to 8.05–8.10 g/cm3, which positively affects the shielding efficiency and strength characteristics. According to the data on the change in strength characteristics, it was found that a change in the density of ceramics from 6.3 to 8.05–8.10 g/cm3 leads to strengthening and an increase in the crack resistance of ceramics by 75–80%, which indicates a high strength of ceramics and their increased resistance to external influences. As shown by the evaluation of the shielding characteristics, an increase in the density of ceramics due to a phase composition change leads to an increase in the shielding efficiency and a decrease in gamma intensity by a factor of 3–3.5. At the same time, on the base of the data presented, it can be concluded that ceramics obtained in the range of 900–1100 °C have both high shielding characteristics and high strength and resistance to external influences.
      Citation: Ceramics
      PubDate: 2023-03-23
      DOI: 10.3390/ceramics6020046
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 818-836: Influence of Defects in Surface Layer of
           Al2O3/TiC and SiAlON Ceramics on Physical and Mechanical Characteristics

    • Authors: Sergey N. Grigoriev, Marina A. Volosova, Anna A. Okunkova, Sergey V. Fedorov
      First page: 818
      Abstract: The paper studies the influence of diamond grinding, lapping, and polishing on the surface layer and defectiveness of the Al2O3/TiC and SiAlON ceramic samples. The index of defectiveness ID, which is the product of the defect density and the defective layer’s thickness (Rt), and a method for its evaluation are proposed to quantify the defectiveness of the ceramic surfaces. Lapping reduces the Rt parameter by 2.6–2.7 times when the density of defects was decreased by 2 times. After polishing, the Rt parameter decreases to 0.42 μm for Al2O3/TiC and 0.37 μm for SiAlON samples. The density of defects decreases many times after polishing: up to 0.005 and 0.004, respectively. The crack resistance of the polished samples increased by 5–7%. The volumetric wear of polished samples decreased by 1.5–1.9 times compared to the ground ones after 20 min of abrasion wear. The polished samples show a decrease in the coefficient of friction at 800 °C and a decrease in the volumetric wear by 1.5 and 1.3 times, respectively, compared to the ground ones after 200 m of friction distance. The volumetric wear at high-temperature friction of sliding for polished specimens was 55% and 42% less than for the ground ones, respectively.
      Citation: Ceramics
      PubDate: 2023-03-24
      DOI: 10.3390/ceramics6020047
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 837-857: Development of Lightweight Geopolymer
           Composites by Combining Various CDW Streams

    • Authors: Dimitrios Kioupis, Aggeliki Skaropoulou, Sotirios Tsivilis, Glikeria Kakali
      First page: 837
      Abstract: This study regards the development of lightweight geopolymer composites through the valorization of various construction and demolition wastes. Brick waste was utilized as the sole aluminosilicate precursor for the geopolymerization reactions, expanded polystyrene and polyurethane wastes were used as artificial lightweight aggregates, and short polyethylene fibers developed from CDWs reinforced the geopolymer matrix. The curing conditions of the geopolymer synthesis were optimized to deliver a robust geopolymer matrix (T = 25–80 °C, t = 24–72 h). Both raw materials and products were appropriately characterized with XRD and SEM, while the mechanical performance was tested through compressive strength, flexural strength, Poisson’s ratio and Young’s modulus measurements. Then, a comprehensive durability investigation was performed (sorptivity, wet/dry cycles, freeze/thaw cycles, and exposure to real weather conditions). In contrast to polyurethane waste, the introduction of expanded polystyrene (0.5–3.0% wt.) effectively reduced the final density of the products (from 2.1 to 1.0 g/cm3) by keeping sufficient compressive strength (6.5–22.8 MPa). The PE fibers could enhance the bending behavior of lightweight geopolymers by 24%; however, a geopolymer matrix–fiber debonding was clearly visible through SEM analysis. Finally, the durability performance of CDW-based geopolymers was significantly improved after the incorporation of expanded polystyrene aggregates and polyethylene fibers mainly concerning freeze/thaw testing. The composite containing 1.5% wt. expanded polystyrene and 2.0% v/v PE fibers held the best combination of properties: Compr. Str. 13.1 MPa, Flex. Str. 3.2 MPa, density 1.4 g/cm3, Young’s modulus 1.3 GPa, and sorptivity 0.179 mm/min0.5.
      Citation: Ceramics
      PubDate: 2023-03-26
      DOI: 10.3390/ceramics6020048
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 858-871: Processing and Tribological Properties of
           PEO Coatings on AlZn5.5MgCu Aluminium Alloy with Incorporated Al-Cu-Fe

    • Authors: Elena V. Torskaya, Alexei V. Morozov, Vladimir N. Malyshev, Olga O. Shcherbakova
      First page: 858
      Abstract: The modification of ceramic PEO coatings developed for friction units is in trend of modern research aimed at the improvement of friction and wear. This study presents ceramic coatings formed on AlZn5.5MgCu aluminum alloy by microarc oxidation (PEO) in a one-stage technological process with inclusions of Al-Cu-Fe quasi-crystals. The technology of rubbing quasi-crystals into the surface of the coating during final polishing was also used. Friction and wear tests, followed by analysis of the surface and cross-sections by SEM microscopy, showed that quasicrystals affect the coating structure and frictional characteristics. The addition of a small amount of modifier to the electrolyte (0.5 percent), as well as rubbing-in technology, can reduce the coefficient of friction (up to 16 percent) and wear rate (up to 43 times) compared to pure ceramic coatings. More modifier provides a negative result.
      Citation: Ceramics
      PubDate: 2023-03-29
      DOI: 10.3390/ceramics6020049
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 872-885: The Influence of the Burning Environment
           on the Properties of Ceramic Products Based on Fusible Raw Materials

    • Authors: Maratbek T. Zhuginissov, Ruslan E. Nurlybayev, Yelzhan S. Orynbekov, Zhanar O. Zhumadilova, Yerlan Y. Khamza, Maxat Z. Bulenbayev
      First page: 872
      Abstract: The purpose of this work was to investigate the effect of the burning environment on the properties and phase composition of clinker-based ceramic specimens made from loam with diatomite and bentonite clay in order to develop technological parameters for the manufacture of clinker products. The main raw material used for the experiments was local fusible loam from the Almaty deposit, which is the basis for the production of 75 and 100 grade ceramic bricks. Diatomite from Utesai deposit (Aktobe region) and highly plastic bentonite clay from Darbazin deposit (Turkestan region) were used as additives. Loam and bentonite clay were applied after grinding and sieving through a 1 mm sieve. Diatomite was applied after grinding and milling until it had completely passed through a 0.315 mm sieve. The raw materials are mixed after dosing, and then water is added in the amount required until a pliable mass is obtained. To investigate the properties of the products, standard cylinder samples were prepared with a diameter of 50 mm and a height of 50 mm. The cylinder samples were pressed on a hydraulic press at a pressure of 2–4 kN. The samples were dried in a desiccator at 95–100 °C for 2 h. After drying, the products were burning in a muffle kiln. The analysis of the properties of the burned products showed that the optimum ratio in the ceramic mixture of loam and diatomite to loam and bentonite clay is 85%:15%. After burning in a slightly oxidising environment at 1170 °C, the ceramic specimens correspond to Class 2 for the medium-density and compressive strength grades M 400 and M 500 (GOST 530-2012 (Government standard). X-ray diffractometric analysis showed that the products contain augite, quartz and anorthite as crystalline phases, with the former predominating. After burning in a reducing atmosphere, at 1170 °C, the properties of the samples have higher values compared to the samples burning in a weakly oxidising atmosphere. The resulting properties, according to the regulations, are characteristic of clinker bricks (DIN V 105-1 (technical requirements for clinker façade bricks). After burning in a reducing environment, the phase composition of the products changes qualitatively; in addition to augite and quartz, albite, diopside, orthoclase and haematite are present in the samples.
      Citation: Ceramics
      PubDate: 2023-03-29
      DOI: 10.3390/ceramics6020050
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 886-897: Ceramic ZnO-SnO2-Fe2O3 Powders and
           Coatings -Effective Photogenerators of Reactive Oxygen Species

    • Authors: Larisa Khomutinnikova, Sergey Evstropiev, Igor Meshkovskii, Igor Bagrov, Valery Kiselev
      First page: 886
      Abstract: Ceramic ZnO-SnO2-Fe2O3 powders and transparent coatings on glasses prepared using the non-isothermal polymer-salt method demonstrate a strong ability to generate chemically active oxygen species under UV and visible irradiation. Crystal structures and morphologies of these materials were studied using the XRD and the SEM analysis. It was found that there are significant differences in the crystal structure of ceramic powders and thin coatings. The powders consist of randomly oriented oxide nanocrystals of size ~47 nm. The strong orientation of the ZnO nanocrystals due to their interaction with the glass substrate is observed in the coating structure. Experimental data show that thin ceramic coatings are transparent (~90%) in the visible spectral range and the band gap of the ceramic material is 3.44 eV. The band gap value of this multi-component ceramic material is described sufficiently using Verlag’s law. Ceramic powders and coatings demonstrate the intensive photogeneration of reactive oxygen species, both in liquid and air. High photocatalytic activity of ZnO-SnO2-Fe2O3 ceramic coatings and powders was observed upon the oxidation of the diazo dye, Chicago Sky Blue. In the presence of transparent photocatalytic coating, the value of the constant rate of the dye photodecomposition was high (k = 0.056 min−1). It was found that, in spite of their short life time, photogenerated reactive oxygen species demonstrate the ability to decompose dye molecules located up to a distance of 0.5 mm from the surface of ceramic coating. Obtained experimental results suggest that the prepared ceramic materials are promising for different practical applications of the photocatalytic materials.
      Citation: Ceramics
      PubDate: 2023-04-02
      DOI: 10.3390/ceramics6020051
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 898-911: A Narrative Review of Recent Finite
           Element Studies Reporting References for Elastic Properties of Zirconia
           Dental Ceramics

    • Authors: Layla A. Abu-Naba’a
      First page: 898
      Abstract: For fixed dentures, new generations of zirconia with diverse characteristics and design choices are of significant interest. Although in vitro studies and finite element analysis (FEA) studies have been published, comprehension of various new methods of material testing and analysis remains insufficient. Young’s modulus and Poisson’s ratio of the desired materials must be available for investigators to validate FEA investigations that are accompanied by mechanical testing. The aim of this narrative review was to find recent FEA studies that report these values for newly developed commercial CAD/CAM zirconia restorative materials and compile them in a data list. A PubMed search was performed (English articles; 2018–2023; keywords: FEA, finite element, zirconia). Full-text articles (157) were examined, including studies (36) reporting the commercial materials’ names, Young’s modulus, and Poisson’s ratio. Only 21 studies had the source of their values referenced. A list of the materials and values used in these studies was compiled. Researchers are highly recommended to trace back references to determine the origins of these values for commercial materials. New research is encouraged to test the ever expanding list of new commercial esthetic monolithic CAD/CAM zirconia materials, as well as their different translucencies, to report their Young’s modulus and Poisson’s ratio.
      Citation: Ceramics
      PubDate: 2023-04-03
      DOI: 10.3390/ceramics6020052
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 912-921: 3D Printing of Ceramic Elements with
           Q-Surface Geometry for the Fabrication of Protective Barrier

    • Authors: Semen V. Diachenko, Andrey S. Dolgin, Nikolai A. Khristyuk, Lev A. Lebedev, Lubov A. Nefedova, Sergey B. Pavlov, Kirill F. Merenkov, Vladimir I. Ivkov, Alla N. Dmitrieva
      First page: 912
      Abstract: The work proposes the use of aluminum oxide-based ceramic objects with a TPMS-Q-surface geometry as elements of armor structures. The samples were produced using the SLA-DLP 3D printing method. The main properties of the sample were determined using physical-chemical analysis methods: apparent density ρap = 3.6 g/cm3, open porosity Popn = 8.5%, microhardness Hµ = 15.3 GPa, water absorption W = 2.4%, elastic modulus E = 405 GPa. The Stiglich criterion M = 1.72 EPa2·m3/kg, and the Shevchenko criterion K = 0.8.
      Citation: Ceramics
      PubDate: 2023-04-03
      DOI: 10.3390/ceramics6020053
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 922-934: Influence of the Preparation Method on
           the Physico-Chemical and Sorption Properties of Montmorillonite

    • Authors: Olga Yu. Golubeva, Elena Yu. Brazovskaya, Yulia A. Alikina
      First page: 922
      Abstract: Layered silicates with a montmorillonite structure are widely used in various fields related to adsorption, gas and water treatment, catalysis, cosmetology and medicine. Under conditions of directed hydrothermal synthesis, montmorillonites with the specified characteristics can be obtained. The influence of the preparation method for montmorillonites of two compositions (Mg3Si4O10(OH)2 H2O and Na1.5Al0.5Mg1.5Si4O10(OH)2 H2O) on their sorption properties, moisture absorption, porous textural characteristics and surface properties has been studied. The nature of the initial reagents, the pH of the reaction medium and the synthesis temperature were chosen as the variable synthesis parameters. It has been established that the synthesis conditions significantly affect the properties of montmorillonite, which, in turn, determines the possibilities of using the materials obtained in specific areas.
      Citation: Ceramics
      PubDate: 2023-04-03
      DOI: 10.3390/ceramics6020054
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 935-947: Drying Behaviour of Al2O3 Inks Containing
           Carboxymethylcellulose (CMC) for Use in Colloidal Processing

    • Authors: Bruno Medeiros da Silva, Ésoly Madeleine Bento dos Santos, Vinícius Zancanelli Bôsco de Souza, Manuel Fellipe Rodrigues Pais Alves, Carlos Maurício Vieira, Claudinei dos Santos
      First page: 935
      Abstract: One of the most important steps in the extrusion processing of ceramic inks is the initial drying of the ceramic parts. This study aimed to investigate the drying behaviour of an Al2O3-based ceramic ink optimised to be processed by extrusion processing methods, e.g., direct ink writing. Carboxymethylcellulose (CMC) was singly added to a suspension of deionised water and Al2O3 (50:50 wt.%) to perform as a dispersing and plasticising agent. To assess moisture loss as a function of time, the ceramic inks were extruded into two types of polymeric moulds: one with a completely closed profile producing cylindrical samples (disks) and one with an open profile producing ceramic bars. After the injection of the inks, the moulds were exposed to different controlled temperatures (20 and 40 °C) for up to 180 h; moisture loss and warpage were periodically measured, and exponential mathematical expressions (moisture loss × drying time) were obtained. The Al2O3-bars dried for 24 h in open moulds at 20 and 40 °C presented longitudinal warpages of 4.5% and 9%, respectively, while the Al2O3 disks dried in closed moulds presented warpages of 3.5% and 7% in these same temperatures (20 and 40 °C, respectively). The samples were sintered at 1610 °C for 4 h and characterised by scanning electron microscopy (SEM), relative density (Archimedes principle), and X-ray diffraction (XRD), presenting a relative density of 92.3 ± 0.5%, α-Al2O3 as crystalline phase and grain with equiaxed morphology varying between 1 and 5 μm.
      Citation: Ceramics
      PubDate: 2023-04-06
      DOI: 10.3390/ceramics6020055
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 948-967: Oxygen–Ion Conductivity, Dielectric
           Properties and Spectroscopic Characterization of “Stuffed”
           Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) Pyrochlores

    • Authors: Nikolay Gorshkov, Egor Baldin, Dmitry Stolbov, Viktor Rassulov, Olga Karyagina, Anna Shlyakhtina
      First page: 948
      Abstract: Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) solid electrolytes have been investigated as potential electrolyte materials for solid oxygen fuel cells (SOFCs), operating in the medium temperature range (600–700 °C). The design of new oxygen-conducting materials is of importance for their possible utilization in the solid oxide fuel cells. The oxygen–ion conductivity of the Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) “stuffed” pyrochlores ceramics was investigated by electrochemical impedance spectroscopy (two-probe AC) in dry and wet air. The synthesis of precursors via co-precipitation and the precipitate decomposition temperature have been shown to be of key importance for obtaining dense and highly conductive ceramics. At ~770 °C, the highest total conductivity, ~3.16 × 10−3 S/cm, is offered by Tm2Ti2O7. The conductivity of the fluorite-like solid solution Tm2(Ti2−xTmx)O7−x/2 (x = 0.74) is an order of magnitude lower. However, for the first time a proton contribution of ~5 × 10−5 S/cm at 600 °C has been found in Tm2(Ti2−xTmx)O7−x/2 (x = 0.74) fluorite. Until now, compositions with proton conductivity were not known for the intermediate and heavy rare earth titanates Ln2(Ti2−xLnx)O7−x/2 (Ln = Ho − Lu) systems. The use of X-ray diffraction (structural analysis with Rietveld refinement), optical spectroscopy and dielectric permittivity data allowed us to follow structural disordering in the solid solution series with increasing thulium oxide content. High and low cooling rates have been shown to have different effects on the properties of the ceramics. Slow cooling initiates’ growth of fluorite nanodomains in a pyrochlore matrix. The fabrication of such nanostructured dense composites is a promising direction in the synthesis of highly conductive solid electrolytes for SOFCs. We assume that high-temperature firing of nanophase precursors helps to obtain lightly doped “stuffed” pyrochlores, which also provide the high oxygen–ion conductivity.
      Citation: Ceramics
      PubDate: 2023-04-10
      DOI: 10.3390/ceramics6020056
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 968-979: Phase Instability, Oxygen Desorption and
           Related Properties in Cu-Based Perovskites Modified by Highly Charged

    • Authors: Roman A. Shishkin, Alexey Yu. Suntsov, Mikhael O. Kalinkin
      First page: 968
      Abstract: The rock-salt ordered A2CuWO6 (A = Sr, Ba) with I4/m space group and disordered SrCu0.5M0.5O3−δ (M = Ta, Nb) with Pm3m space group perovskites were successfully obtained via a solid-state reaction route. Heat treatment of Ba2CuWO6 over 900 °C in air leads to phase decomposition to the barium tungstate and copper oxide. Thermogravimetric measurements reveal the strong stoichiometric oxygen content and specific oxygen capacity (ΔWo) exceeding 2.5% for Ba2CuWO6. At the same time, oxygen content reveals Cu3+ content in SrCu0.5Ta0.5O3−δ. Under the following reoxidation of Ba2CuWO6, step-like behavior in weight changes was observed, corresponding to possible Cu+ ion formation at 900 °C; in contrast, no similar effect was detected for M5+ cations. The yellow color of Ba2CuWO6 enables to measure the band gap 2.59 eV. SrCu0.5Ta0.5O3−δ due to high oxygen valance concentration has a low thermal conductivity 1.28 W·m−1·K−1 in the temperature range 25–400 °C.
      Citation: Ceramics
      PubDate: 2023-04-11
      DOI: 10.3390/ceramics6020057
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 980-993: Surface Modification of Silica
           Nanoparticles with Ethyl Oleate for the Purpose of Stabilizing
           Nanolubricants Used for Tribological Tests

    • Authors: Álmos Dávid Tóth, Nóra Mike-Kaszás, Gábor Bartus, Hajnalka Hargitai, Ádám István Szabó
      First page: 980
      Abstract: Long-term sustainability and decreasing amount of fossil oil reserves require a partial or complete transformation of traditional lubricating oils. The use of silica nanoparticles as a lubricant additive has a huge tribological potential, which has already been discussed in numerous articles. Nanosized silica shows excellent results in reducing friction and preventing wear, but they quickly aggregate and settle after homogenization in oils. For long-term stable dispersion of lubricating oils containing nanoceramics, the surface of the particles was modified with ethyl oleate. The surface modification, the ethyl oleate applied to the surface of the nanosilica, was confirmed by Fourier-transform infrared spectroscopy. Group III based lubricating oil was prepared using the surface-modified nanosilica. The particle size of the nanoparticles in the lubricating oil dispersion was examined by dynamic light scattering. Oscillating tribometer measurements were performed with different concentrations (0.1; 0.2; 0.3 wt%) of nanolubricants. Based on the tribological results, the friction coefficient of the surface-modified nanosilica is more stable, its wear is 15% lower compared to the reference. There is no significant change in the magnitude of the friction coefficient. It can be concluded that the ethyl oleate surface modification method may be suitable for tribological investigations of the acting mechanisms of nanoparticles.
      Citation: Ceramics
      PubDate: 2023-04-13
      DOI: 10.3390/ceramics6020058
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 994-1016: Non-Oxide Ceramics for Bone Implant
           Application: State-of-the-Art Overview with an Emphasis on the Acetabular
           Cup of Hip Joint Prosthesis

    • Authors: Consiglio M. Paione, Francesco Baino
      First page: 994
      Abstract: A rapidly developing area of ceramic science and technology involves research on the interaction between implanted biomaterials and the human body. Over the past half century, the use of bioceramics has revolutionized the surgical treatment of various diseases that primarily affect bone, thus contributing to significantly improving the quality of life of rehabilitated patients. Calcium phosphates, bioactive glasses and glass-ceramics are mostly used in tissue engineering applications where bone regeneration is the major goal, while stronger but almost inert biocompatible ceramics such as alumina and alumina/zirconia composites are preferable in joint prostheses. Over the last few years, non-oxide ceramics—primarily silicon nitride, silicon carbide and diamond-like coatings—have been proposed as new options in orthopaedics in order to overcome some tribological and biomechanical limitations of existing commercial products, yielding very promising results. This review is specifically addressed to these relatively less popular, non-oxide biomaterials for bone applications, highlighting their potential advantages and critical aspects deserving further research in the future. Special focus is also given to the use of non-oxide ceramics in the manufacturing of the acetabular cup, which is the most critical component of hip joint prostheses.
      Citation: Ceramics
      PubDate: 2023-04-19
      DOI: 10.3390/ceramics6020059
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1017-1030: Preparation and Mechanical
           Characteristics of Multicomponent Ceramic Solid Solutions of Rare Earth
           Metal Oxides Synthesized by the SCS Method

    • Authors: Victor Zhuravlev, Larisa Ermakova, Rina Samigullina, Alexey Ermakov
      First page: 1017
      Abstract: A study into the use of the Solution Combustion Synthesis (SCS) method with glycine and citric acid to synthesize fine powders of multicomponent solid solutions of oxides of rare earth (RE) metals (Nd, Sm, Eu, Gd, Dy, and Ho) for the preparation of ceramic materials is presented. Synthesis parameters of 4-, 5-, and 6-component entropy-stabilized rare earth oxides (REOs) with a C-type cubic structure are determined. The stability of entropy-stabilized oxides (ESOs) with a C-type structure is shown to depend not only on heavy RE metal quantity, but also on the rate of heating/cooling of the samples. The temperature of the polymorphic transformation of C-type REO structures into B-type (monoclinic) or H-type (hexagonal) structural variants can be described by the equation T (°C) = 0.0214Vcr2 − 62.737Vcr + 46390, where Vcr is the unit cell volume of an oxide with a C-type structure regardless of the number of cations in the solid solution. High-temperature thermal analysis up to 1250 °C revealed that dispersed powders, which contain impurities of basic carbonates along with hydroxocarbonates of RE metals and X-ray amorphous carbon formed during SCS reactions, also react with air moisture during storage. The influence of the ESO phase and cationic composition on the morphology, porosity and microhardness of ceramics was studied. Higher-entropy oxides form samples with higher density, microhardness and a smaller size of particle agglomerates.
      Citation: Ceramics
      PubDate: 2023-04-22
      DOI: 10.3390/ceramics6020060
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1031-1049: Mechanical Properties of Five Esthetic
           Ceramic Materials Used for Monolithic Restorations: A Comparative In Vitro

    • Authors: Saleh N. Almohammed, Belal Alshorman, Layla A. Abu-Naba’a
      First page: 1031
      Abstract: Monolithic zirconia and hybrid ceramic restorations have been widely used in the last decade for both anterior and posterior dental restorations. However, their use lacks sufficient scientific evidence in most cases, as the expeditious manufacturing of these versatile ceramic materials exceeds the limits of in vitro and/or in vivo validation. This study aimed to evaluate and compare the mechanical properties (flexural strength, fracture toughness, Vickers hardness, and brittleness index) of three CAD-CAM monolithic multilayer zirconia ceramics (GNX—Ceramill Zolid® Gen-X, ZCP—IPS e.max® ZirCAD, and UPC—Upcera® Esthetic Explore Prime) and one CAD-CAM monolithic multilayer polymer-infiltrated hybrid ceramic (ENM—Vita® Enamic) with a CAD-CAM monolithic lithium disilicate ceramic as a control (EMX —IPS e.max® CAD). A total of 160 discs (GNX = 32, ZCP = 32, UPC = 32, ENM = 32, and EMX = 32) were cut, polished, and fully sintered (except for the ENM). Half of the samples for each group were subjected to hydrothermal aging. Descriptive analysis and ANOVA tests were used to compare the groups. The zirconia groups showed significantly higher mechanical properties than the EMX group for both the non-aged and aged samples (p < 0.05). The ENM group showed the lowest brittleness index, while EMX showed the highest. The mechanical properties of monolithic multilayer zirconia ceramics were generally better than those of monolithic multilayer polymer-infiltrated hybrid ceramic and lithium disilicate ceramic. All groups showed, to some extent, a change in their mechanical properties after aging, with the ENM being the most affected.
      Citation: Ceramics
      PubDate: 2023-04-24
      DOI: 10.3390/ceramics6020061
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1050-1066: On the Statistics of Mechanical Failure
           in Flame-Sprayed Self-Supporting Components

    • Authors: Florian Kerber, Magda Hollenbach, Marc Neumann, Tony Wetzig, Thomas Schemmel, Helge Jansen, Christos G. Aneziris
      First page: 1050
      Abstract: The objective of this study was to investigate the variability of flexural strength for flame-sprayed ceramic components and to determine which two-parametric distribution function was best suited to represent the experimental data. Moreover, the influence of the number of tested specimens was addressed. The stochastic nature of the flame-spraying process causes a pronounced variation in the properties of potential components, making it crucial to characterise the fracture statistics. To achieve this, this study used two large data sets consisting of 1000 flame-sprayed specimens each. In addition to the standard Weibull approach, the study examined the quality of representing the experimental data using other two-parametric distribution functions (Normal, Log-Normal, and Gamma). To evaluate the accuracy of the distribution functions and their characteristic parameters, random subsamples were generated by resampling of the experimental data, and the results were assessed based on the sampling size. It was found that the experimental data were best represented by either the Weibull or Gamma distribution, and the quality of the fit was correlated with the number of positive and negative outliers. The Weibull fit was more sensitive to positive outliers, whereas the Gamma fit was more sensitive to negative outliers.
      Citation: Ceramics
      PubDate: 2023-04-25
      DOI: 10.3390/ceramics6020062
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1067-1077: Digital Characteristics of
           Microstructure of Diamond—Silicon Carbide Composites

    • Authors: Andrey G. Chekuryaev, Maxim M. Sychov, Sergey N. Perevislov, Vladimir N. Ulanov
      First page: 1067
      Abstract: As an example of the implementation of digital materials science approaches based on statistical processing of electron micrographs with the analysis of fractal parameters, the digital characteristics of microstructure of diamond–silicon carbide ceramic composite material are calculated. The lacunarity parameter characterizing the non-uniform distribution of filler particles in the matrix is found. Based on lacunarity values calculated at different scales, scale invariance parameter characterizing the dependence of lacunarity on the scale is evaluated. Voronoi entropy characterizing the structure based on the quantity of information is also calculated and used to determine the average number of neighboring particles and average distance between them. For the composites with high mechanical properties, the number of nearest neighbors approaches six, indicating an almost closest packing.
      Citation: Ceramics
      PubDate: 2023-05-01
      DOI: 10.3390/ceramics6020063
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1078-1099: Red and Black Paints on Prehistoric
           Pottery of the Southern Russian Far East: An Archaeometric Study

    • Authors: Irina S. Zhushchikhovskaya, Igor Yu Buravlev, Aleksander A. Karpenko, Anastasia A. Lazina, Aleksander N. Fedorets
      First page: 1078
      Abstract: This paper considers the results of an examination of painted pottery from prehistoric sites of the Prmor’ye region (Southern Russian Far East) in the northwestern part of the Sea of Japan basin. Red-painted and black-painted ceramic wares occur here only in the remains of the Yankovskaya archaeological culture dated to the 1st mil. BCE. Red painting appears as a colored surface coating, and black painting is represented by very simple drawn patterns. Until recently painting decorations have not been intentionally studied. The objects of our investigation are a small series of red-painted and black-painted ceramic fragments originated from archaeological sites. The methods of optical microscopy, SEM-EDS, and Raman spectroscopy were applied to the study of research materials. As a result, the data on characteristics of texture and composition of red and black paints were obtained. Both were determined to be pre-firing paints. Red paint is a clayish substance mixed with natural ochre pigment containing the hematite coloring agent. Black paint is carbon-based. Black carbon and burnt bone are recognized as colorants. The presented materials are new evidence of pottery paint technologies in prehistoric Eurasia.
      Citation: Ceramics
      PubDate: 2023-05-02
      DOI: 10.3390/ceramics6020064
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1100-1112: Effect of Synthetic Approaches and
           Sintering Additives upon Physicochemical and Electrophysical Properties of
           Solid Solutions in the System (CeO2)1−x(Nd2O3)x for Fuel Cell

    • Authors: Marina V. Kalinina, Daria A. Dyuskina, Irina G. Polyakova, Sergey V. Mjakin, Irina Yu. Kruchinina
      First page: 1100
      Abstract: Finely dispersed (CeO2)1−x(Nd2O3)x (x = 0.05, 0.10, 0.15, 0.20, 0.25) powders are synthesized via liquid-phase techniques based on the co-precipitation of hydroxides and co-crystallization of nitrates. The prepared powders are used to obtain ceramic materials comprising fluorite-like solid solutions with the coherent scattering region (CSR) of about 88 nm (upon annealing at 1300 °C) and open porosity in the range of 1–15%. The effect of the synthesis procedure and sintering additives (SiO2, ZnO) on physicochemical and electrophysical properties of the resulting ceramics is studied. The prepared materials are found to possess a predominantly ionic type of electric conductivity with ion transfer numbers ti = 0.96–0.71 in the temperature range of 300–700 °C. The conductivity in solid solutions follows a vacancy mechanism with σ700 °C = 0.48 × 10−2 S/cm. Physicochemical properties (density, open porosity, type and mechanism of electrical conductivity) of the obtained ceramic materials make them promising as solid oxide electrolytes for medium temperature fuel cells.
      Citation: Ceramics
      PubDate: 2023-05-11
      DOI: 10.3390/ceramics6020065
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1113-1128: Water-Assisted Cold Sintering of
           Alumina Ceramics in SPS Conditions

    • Authors: Anastasia A. Kholodkova, Maxim V. Kornyushin, Mikhail A. Pakhomov, Andrey V. Smirnov, Yurii D. Ivakin
      First page: 1113
      Abstract: A developing energy-saving approach of cold sintering in a pure aqueous medium was applied to the preparation of α-Al2O3 ceramics and performed on spark plasma sintering equipment. The initial γ-Al(OH)3 and γ-AlOOH powders and the cold-sintered ceramics were studied by X-ray diffraction analysis, infrared spectroscopy, thermal analysis, and scanning electron microscopy to reveal the chemical and structural transformations they experienced during the cold sintering. At 450 °C and 70 MPa, initially γ-AlOOH transformed into a fragile α-Al2O3 material. Porous α-Al2O3 ceramics with about 60% porosity were obtained after cold sintering of γ-Al(OH)3 in the same conditions combined with subsequent annealing at 1250 °C for 3 h. The role of water molecules in the studied processes was considered as the enhancement of structural mobility in the cold-sintered material due to its reversible hydroxylation similar to earlier investigated supercritical water actions on the precursors during α-Al2O3 formation. Further improvement of the cold sintering setup and regimens would open prospects in α-Al2O3 ceramics manufacturing by an ecologically benign route.
      Citation: Ceramics
      PubDate: 2023-05-17
      DOI: 10.3390/ceramics6020066
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1129-1138: Hafnium-Zirconium Carbonitride
           (Hf,Zr)(C,N) by One Step Mechanically Induced Self-Sustaining Reaction:
           Powder Synthesis and Spark Plasma Sintering

    • Authors: Irina Khadyrova, Veronika Suvorova, Andrey Nepapushev, Dmitrii Suvorov, Kirill Kuskov, Dmitry Moskovskikh
      First page: 1129
      Abstract: Nanostructured single-phase hafnium-zirconium carbonitride powders were synthesized using a simple and fast mechanochemical synthesis approach. The critical milling duration, after which a (Hf,Zr)(C,N) solid solution formation inside a jar occurred via mechanically induced self-sustained reaction (MSR), was 10 min. After 30 min of treatment, a solid-gas reaction was completed, and as a result, a homogeneous (Hf,Zr)(C,N) powder consisting of 10–500 nm submicron particles was obtained. The phase and structure evolution of the powders after different treatment durations allowed for the establishment of possible reaction mechanisms, which included the formation of Hf/Zr/C-layered composite particles, their interaction via MSR, and further grinding and nitridization. Spark plasma sintering (SPS) was used to produce bulk hafnium-zirconium carbonitride ceramics from nanostructured powder. The sample had higher values of relative density, hardness, and fracture toughness than those for binary compounds of a similar composition.
      Citation: Ceramics
      PubDate: 2023-05-17
      DOI: 10.3390/ceramics6020067
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1139-1151: Obtaining Foamed Glass-Ceramics from
           Diamond Concentration Tailings

    • Authors: Olga V. Suvorova, Nadezhda K. Manakova, Andrey I. Novikov, Dmitriy V. Makarov
      First page: 1139
      Abstract: The possibility of obtaining building foamed glass-ceramic using the diamond concentration tailings of the Lomonosov deposit in Arkhangelsk Region, Russia, is demonstrated here. The effect of the tailings’ particle size distribution, feed temperature, the addition of a foaming agent, and the content of oxidizer on the feed charge foaming is established. The process conditions for obtaining foamed glass-ceramic materials are described. The specifications of the materials with the optimal composition (tailings 50 wt.%, glass waste 50 wt.%, SiC 0.5 wt.%, Fe2O3 1 wt.%) foamed at 1020–1050 °C were as follows: apparent density 0.23–0.51 g/cm3, compression strength 0.58–2.40 MPa, water absorption (by volume) 8.7–19.0%. Based on the combination of the measured properties when used in dry conditions, the obtained materials can be considered heat-insulating foam materials. The thermal conductivity was 0.060–0.066 W/m·K.
      Citation: Ceramics
      PubDate: 2023-05-18
      DOI: 10.3390/ceramics6020068
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1152-1163: Uranium Retention in Silica-Rich
           Natural Glasses: Nuclear Waste Disposal Aspect

    • Authors: Valeri V. Poluektov, Vladislav A. Petrov, Michael I. Ojovan, Sergey V. Yudintsev
      First page: 1152
      Abstract: Uranium-containing glass samples with an age of 140–145 million years were collected within the volcanic rocks of the largest volcanic-related uranium ore deposit in the world. Main features of their composition are high concentrations of silica and uranium, the largest for the rocks of this type. In contrast to this, the ages of fresh (unaltered) low-silica natural glasses of a basic composition (basalts) usually do not exceed a few million years. The volcanic low-silica glass is unstable at longer times and in older ancient rocks is transformed into a crystalline mass. The geochemistry of uranium including the behavior in solids and solutions is similar to that of long-lived transuranic actinides such as radioactive Np and Pu from high-level radioactive waste. This allows uranium to be used as a simulant of these long-lived hazardous radionuclides both at the synthesis and for the study of various nuclear wasteforms: glasses, glass crystalline materials and crystalline ceramics. The data obtained on long-term behavior of natural glasses are of importance for prognosis and validation of stability of nuclear wasteforms disposed of in geological disposal facilities (GDF).
      Citation: Ceramics
      PubDate: 2023-05-18
      DOI: 10.3390/ceramics6020069
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1164-1178: Study of the Mechanisms of Polymorphic
           Transformations in Zirconium Dioxide upon Doping with Magnesium Oxide, as
           Well as Establishing the Relationship between Structural Changes and
           Strength Properties

    • Authors: Alisher E. Kurakhmedov, Aidar K. Morzabayev, Islam Tleubay, Askhat Berguzinov, Artem L. Kozlovskiy
      First page: 1164
      Abstract: The aim of this work is to study the mechanisms of polymorphic transformations in ZrO2 ceramics doped with MgO with different concentrations during thermal isochronous annealing, as well as the effect of the phase composition of ceramics on the change in strength properties and resistance to mechanical stress. Solving the problem of polymorphic transformations in zirconium dioxide by doping them with MgO will increase the resistance of ceramics to external influences, as well as increase the mechanical strength of ceramics. According to the data of X-ray phase analysis, it was found that the addition of the MgO dopant to the composition of ceramics at the chosen thermal annealing temperature leads to the initialization of polymorphic transformation processes, while changing the dopant concentration leads to significant differences in the types of polymorphic transformations. In the case of an undoped ZrO2 ceramic sample, thermal annealing at a temperature of 1500 °C leads to structural ordering due to the partial removal of deformation distortions of the crystal lattice caused by mechanochemical grinding. During the study of the effect of MgO doping and polymorphic transformations in ZrO2 ceramics on the strength properties, it was found that the main hardening effect is due to a change in the dislocation density during the formation of a ZrO2/MgO type structure. At the same time, polymorphic transformations of the m—ZrO2 → t—ZrO2 type have a greater effect on hardening at low dopant concentrations than t—ZrO2 → c—ZrO2 type transformations.
      Citation: Ceramics
      PubDate: 2023-05-24
      DOI: 10.3390/ceramics6020070
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1179-1190: Comparative Fracture Resistance
           Analysis of Translucent Monolithic Zirconia Dioxide Milled in a CAD/CAM

    • Authors: Cristian Abad-Coronel, Ángeles Paladines, Ana Liz Ulloa, César A. Paltán, Jorge I. Fajardo
      First page: 1179
      Abstract: The aim of this study was to evaluate and compare the fracture resistance of definitive zirconia dioxide restorations obtained using a computer-aided design and manufacturing (CAD/CAM) system. Methods: Two groups of ten samples were analyzed for each material (n: 20); the first group was Zolid Gen X Amann Girrbach (ZGX) and the second group was Cercon HT Dentsply Sirona (CDS). The restorations were designed with identical parameters and milled with a CAD/CAM system. Each specimen was load tested at a speed of 0.5 mm/min, with a direction parallel to the major axis of the tooth and with an initial preload of 10 N until fracture using a universal testing machine (Universal/Tensile Testing Machine, Autograph AGS-X Series) equipped with a 20 kN load cell. The results obtained were recorded in Newtons (N), using software connected to the testing machine. Results: Statistically significant differences were found, and the fracture resistance of the monolithic zirconia crowns was lower in the CDS group (1744.84 ± 172.8 N) compared to the ZGX group (2387.41 ± 516 N). Conclusions: The monolithic zirconia CAD-CAM zirconia crowns showed sufficient fracture resistance when used in posterior molar and premolar zones with either material, as they withstood fracture loads greater than the maximum masticatory force.
      Citation: Ceramics
      PubDate: 2023-05-31
      DOI: 10.3390/ceramics6020071
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1191-1209: Mechanical Behavior of Transparent
           Spinel Fabricated by Spark Plasma Sintering

    • Authors: Khadidja Hoggas, Salim Benaissa, Abdelbaki Cherouana, Sofiane Bouheroum, Abdenacer Assali, Mohamed Hamidouche, Gilbert Fantozzi
      First page: 1191
      Abstract: In this work, a transparent nanostructured ceramic magnesium aluminate spinel (MgAl2O4) was fabricated by Spark Plasma Sintering (SPS) from commercial spinel nano-powders at different temperatures (1300, 1350 and 1400 °C). The sintered samples were thoroughly examined to assess their microstructural, optical, and mechanical properties. Various techniques such as SEM, AFM, spectrophotometer with an integrating sphere, instrumented Vickers indenter, Pin-on-Disk tribometer, scratch tester, and sandblasting device were employed to characterize the sintered samples. The results indicated the significant impact of the sintering temperature on the properties of the spinel samples. Particularly, the samples sintered at T = 1350 °C exhibited the highest Real In-line Transmission (RIT = 72% at 550 nm and 80% at 1000 nm). These samples demonstrated the highest hardness value (HV = 16.7 GPa) compared to those sintered at 1300 °C (HV = 15.6 GPa) and 1400 °C (HV = 15.1 GPa). The measured fracture toughness of the sintered samples increased substantially with increasing sintering temperature. Similarly, the tribological study revealed that the friction coefficient of the sintered spinel samples increased with the sintering temperature, and the spinel sintered at 1350 °C exhibited the lowest wear rate. Additionally, sandblasting and scratch tests confirmed the significant influence of the sintering temperature on the mechanical properties of the fabricated spinels. Overall, the spinel sintered at 1350 °C presented the best compromise in terms of all the evaluated properties.
      Citation: Ceramics
      PubDate: 2023-05-31
      DOI: 10.3390/ceramics6020072
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1210-1226: Comparative Study of Physicochemical
           Properties of Finely Dispersed Powders and Ceramics in the Systems
           CeO2–Sm2O3 and CeO2–Nd2O3 as Electrolyte Materials for Medium
           Temperature Fuel Cells

    • Authors: Marina V. Kalinina, Daria A. Dyuskina, Sergey V. Mjakin, Irina Yu. Kruchinina, Olga A. Shilova
      First page: 1210
      Abstract: Finely dispersed (CeO2)1−x(Sm2O3)x (x = 0.05, 0.10, 0.20) and (CeO2)1−x(Nd2O3)x (x = 0.05, 0.10, 0.15, 0.20, 0.25) powders were synthesized via liquid-phase techniques based on the co-precipitation of hydroxides and were used to obtain ceramic materials comprising fluorite-like solid solutions with CSR in the range 69–88 nm (upon annealing at 1300 °C) and open porosity in the range 0.6–6.2%. The physicochemical properties of the synthesized materials were comparatively characterized. In general, the prepared materials were found to possess a mixed type of electrical conductivity, but in the medium-temperature range, the ionic component was predominant (ion transfer numbers ti = 0.93–0.73 at 300–700 °C). The highest ionic conductivity was observed for CeO2-based samples containing 20 mol.% Sm2O3 (σ700°C = 3.3 × 10−2 S/cm) and 15 mol.% Nd2O3 (σ700°C = 0.48 × 10−2 S/cm) was in the temperature range 500–700 °C. The physicochemical properties (density, open porosity, type and mechanism of electrical conductivity) of the obtained ceramic materials make them promising as solid oxide electrolytes for medium temperature fuel cells.
      Citation: Ceramics
      PubDate: 2023-06-04
      DOI: 10.3390/ceramics6020073
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1227-1237: Structural-Phase Change of Multilayer
           Ceramics Zr-Y-O/Si-Al-N under High Temperature

    • Authors: Marina Fedorischeva, Mark Kalashnikov, Irina Bozhko, Tamara Dorofeeva, Victor Sergeev
      First page: 1227
      Abstract: To increase the thermocyclic resistance of material, multilayer coatings with alternating layers of Zr-Y-O and Si-Al-N were obtained via magnetron sputtering. It was established that a coating layer based on Zr-Y-O has a columnar structure; the height of the columns is determined by the thickness of the layer. The Si-Al-N-based layer is amorphous. There were monoclinic and tetragonal phases with a large lattice parameter in the composition of the Zr-Y-O-based coating layer. After high-temperature annealing, a tetragonal phase with a small lattice parameter appeared in the microscope column. In the “in situ” mode, a change in the structural state of the Zr-Y-O coating layer was detected in the temperature range of 450–500 °C; namely, a change in the grain size and coherent scattering regions, and an increase in internal elastic stresses. It was found that the thermocyclic resistance increased by more than two times for multilayer samples compared to the single-layer ones we studied earlier.
      Citation: Ceramics
      PubDate: 2023-06-08
      DOI: 10.3390/ceramics6020074
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1238-1250: Comparative Study of Mechanical

    • Authors: Jing Liang, Marc Serra, Sandra Gordon, Jonathan Fernández de Ara, Eluxka Almandoz, Luis Llanes, Emilio Jimenez-Piqué
      First page: 1238
      Abstract: The objective of this study is to explore and compare the mechanical response of AlCrSiN coatings deposited on two different substrates, namely, WC-Co and cBN. Nano-indentation was used to measure the hardness and elastic modulus of the coatings, and micro-indentation was used for observing the contact damage under Hertzian contact with monotonic and cyclic (fatigue) loads. Microscratch and contact damage tests were also used to evaluate the strength of adhesion between the AlCrSiN coatings and the two substrates under progressive and constant loads, respectively. The surface damages induced via different mechanical tests were observed using scanning electron microscopy (SEM). A focused ion beam (FIB) was used to produce a cross-section of the coating–substrate system in order to further detect the mode and extent of failure that was induced. The results show that the AlCrSiN coating deposited on the WC-Co substrate performed better in regard to adhesion strength and contact damage response than the same coating deposited on the cBN substrate; this is attributed to the lower plasticity of the cBN substrate as well as its less powerful adhesion to the coating.
      Citation: Ceramics
      PubDate: 2023-06-09
      DOI: 10.3390/ceramics6020075
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1251-1262: Fe Doping in TiO2 via Anodic
           Dissolution of Iron: Synthesis, Characterization, and Electrophoretic
           Deposition on a Metal Substrate

    • Authors: Sara Chatrnoor, Amirhossein Taghaddosi, Sayed Ali Ahmad Alem, Fatemeh Taati-Asil, Babak Raissi, Reza Riahifar, Maziar Sahba Yaghmaee
      First page: 1251
      Abstract: The tailored physical properties of TiO2 are of significant importance in various fields and, as such, numerous methods for modifying these properties have been introduced. In this study, we present a novel method for doping Fe into TiO2 via the anodic dissolution of iron. The optimal conditions were determined to be an application of 200 V to acetylacetone (acac)/EtOH medium for 10 min, followed by the addition of TiO2 to the solution, sonication for 30 min, stirring at 80 °C, and drying. The resulting powder was calcined at 400 °C for 3 h, and characterization was conducted using XRD, FTIR, TEM, and UV-vis. The synthesized powder revealed the successful doping of Fe into the TiO2 structure, resulting in a decrease in the optical band gap from 3.22 to 2.92 eV. The Fe-TiO2 was then deposited on a metal substrate via the electrophoretic (EPD) technique, and the weight of the deposited layer was measured as a function of the applied voltage and exposure time. FESEM images and EDX analysis confirmed that the deposited layer was nanostructured, with Fe evenly distributed throughout the structure.
      Citation: Ceramics
      PubDate: 2023-06-13
      DOI: 10.3390/ceramics6020076
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1263-1276: Revealing the Individual Effects of
           Firing Temperature and Chemical Composition on Raman Parameters of Celadon

    • Authors: Lan Zhao, Yunjun Zhang
      First page: 1263
      Abstract: The Raman polymerization index (or IP value) is often used as a positive indicator of the firing temperature of the glazes of ancient ceramics. Previous studies have also reported that the IP value was negatively correlated with the chemical composition of the glaze. However, these findings were derived from data on the potential integrative effects of temperature and composition. To explore their individual effects, we prepared celadon glaze samples with controlled composition and firing temperatures. Particularly, according to the typical content of K2O and CaO in celadon glaze, four categories, or, in total, fifteen compositional formulations, were designed, and each formulation was fired at multiple temperatures (from 1180 to 1250 °C by 10 °C). The chemical compositions and the glassy matrix of samples were analyzed by an energy-dispersive X-ray fluorescence spectrometer and Raman spectroscopy, respectively. A positive correlation between firing temperature and IP value (correlation coefficient = 0.56) was detected only in the samples with low contents of K2O and CaO. However, no significant correlation was found when combining the samples with broad variation in chemical composition. Additionally, both the K2O content and CaO content were negatively related to the IP value, with regression coefficients of −9.645 and −5.332, respectively. Our results help to clarify the technology of ancient ceramic production and to improve its preservation.
      Citation: Ceramics
      PubDate: 2023-06-14
      DOI: 10.3390/ceramics6020077
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1277-1290: Investigation of the Quartz
           Distribution in Electro-Porcelain Materials

    • Authors: Fanni Senze, Sören Höhn, Björn Matthey, Jan Schulte-Fischedick, Mathias Herrmann
      First page: 1277
      Abstract: Analysis of the microstructure of electro-porcelain is important to better understand its influence on mechanical, electrical and aging behavior. The microstructures of two electro-porcelain materials with low and high quartz contents were analyzed with respect to the distribution of quartz. Using an adequate evaluation of EDS (energy dispersive spectroscopy) mapping data, a reproducible analysis of the size distribution and quantity of quartz was achieved. The method allows the analysis of large areas (12.5 mm2). Therefore, the probability of occurrence for a few large quartz grains could be determined. Independent of the overall amount of quartz in the materials, a wide distribution of the grain size was observed. The size of the large detected quartz grains in both materials was very similar. Around the large quartz particles, microcrack systems with lengths of several 100 µm were observed. They are linearly correlated with the equivalent circle diameter of the quartz grains. The evaluation of the cracks allowed us to determine the critical size below which no cracks around the quartz particles are formed. This size is approximately 10 µm.
      Citation: Ceramics
      PubDate: 2023-06-14
      DOI: 10.3390/ceramics6020078
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 1291-1301: Infrared and Terahertz Spectra of
           Sn-Doped Vanadium Dioxide Films

    • Authors: Alexander Grebenchukov, Olga Boytsova, Alexey Shakhmin, Artem Tatarenko, Olga Makarevich, Ilya Roslyakov, Grigory Kropotov, Mikhail Khodzitsky
      First page: 1291
      Abstract: This work reports the effect of tin (Sn) doping on the infrared (IR) and terahertz (THz) properties of vanadium dioxide (VO2) films. The films were grown by hydrothermal synthesis with a post-annealing process and then fully characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and temperature-controlled electrical resistivity as well as IR and THz spectroscopy techniques. Utilizing (NH4)2SnF6 as a Sn precursor allows the preparation of homogeneous Sn-doped VO2 films. Doping of VO2 films with Sn led to an increase in the thermal hysteresis width while conserving the high modulation depth in the mid-IR regime, which would be beneficial for the applications of VO2 films in IR memory devices. A further analysis shows that Sn doping of VO2 films significantly affects the temperature-dependent THz optical properties, in particular leading to the suppression of the temperature-driven THz transmission modulation. These results indicate Sn-doped VO2 films as a promising material for the development of switchable IR/THz dichroic components.
      Citation: Ceramics
      PubDate: 2023-06-15
      DOI: 10.3390/ceramics6020079
      Issue No: Vol. 6, No. 2 (2023)
  • Ceramics, Vol. 6, Pages 678-685: Process Development of Zirconolite
           Ceramics for Pu Disposition: Use of a CuO Sintering Aid

    • Authors: Aidan A. Friskney, Ismail Aldean, Claire L. Corkhill, Lewis R. Blackburn
      First page: 678
      Abstract: Zirconolite-structured ceramics are candidate wasteform materials for the immobilisation of separated Pu. Due to the refractory properties of zirconolite and other titanates, removing residual porosity remains challenging in the final wasteform product when utilising a conventional solid state sintering route. Herein, we demonstrate that the addition of CuO as a sintering aid increases densification and promotes grain growth. Moreover, zirconolite phase formation was enhanced at lower process temperatures than typically required (≥1350 °C). CuO addition allowed an equivalent density to be reached using process temperatures of 250 °C lower than the undoped composition. At 150 °C lower than the undoped zirconolite, the addition of CuO resulted in a favourable microstructure and phase assemblage, as confirmed via X-ray diffraction and scanning electron microscopy. Secondary phases of CaTiO3 and Ca0.25Cu0.75TiO3 were observed at some processing temperatures, which may prove deleterious to wasteform performance. The use of a CuO sintering aid provides an avenue for the further development of the thermal processing of ceramic wasteform materials.
      Citation: Ceramics
      PubDate: 2023-03-08
      DOI: 10.3390/ceramics6010041
      Issue No: Vol. 6, No. 1 (2023)
  • Ceramics, Vol. 6, Pages 686-706: Study of Polymorphic Transformation
           Processes and Their Influence in Polycrystalline ZrO2 Ceramics upon
           Irradiation with Heavy Ions

    • Authors: Artem L. Kozlovskiy, Mahambet Alin, Daryn B. Borgekov
      First page: 686
      Abstract: The aim of this work was to study the mechanisms of polymorphic transformations in ZrO2 ceramics under irradiation with heavy ions, as well as to determine the nature of structural distortions in the case of t-ZrO2 → c-ZrO2 type transformations and associated anisotropic deformations. The samples of ZrO2 ceramics were irradiated with Kr15+ heavy ions with an energy of 150 MeV and fluences of 1011–1016 ion/cm2. During evaluation of the structural changes depending on the irradiation fluence, it was found that at low irradiation fluences (1011–1012 ion/cm2), the main role is played by deformation distortions of the crystal lattice, which have a pronounced anisotropic character. Meanwhile, at fluences above 1013 ion/cm2, the main role is played by polymorphic transformations of the t-ZrO2 → c-ZrO2 type, followed by amorphization of the damaged layer at fluences above 1015 ion/cm2. It was established that the anisotropic distortion of the crystal lattice is more pronounced along the crystallographic a axis, as well as the (011) texture orientation, which is characteristic of t-ZrO2. The polymorphic transformation processes of the t-ZrO2 → c-ZrO2 type occur at irradiation fluences of 1013–1014 ions/cm2, which are characterized by the formation of an overlap of local areas of defects that appear along the trajectory of ions in the material. The dependences of changes in the strength and thermophysical properties of ZrO2 ceramics on the irradiation fluence were obtained. The mechanisms of influence of the structural disorder and polymorphic transformations on the decrease in strength and crack resistance were established.
      Citation: Ceramics
      PubDate: 2023-03-10
      DOI: 10.3390/ceramics6010042
      Issue No: Vol. 6, No. 1 (2023)
  • Ceramics, Vol. 6, Pages 707-716: Investigation of the Effect of Milling
           Duration on a Ce-Gd Doped Zirconolite Phase Assemblage Synthesised by Hot
           Isostatic Pressing

    • Authors: Merve Kuman, Laura J. Gardner, Lewis R. Blackburn, Martin C. Stennett, Neil C. Hyatt, Claire L. Corkhill
      First page: 707
      Abstract: Zirconolite is a candidate ceramic wasteform under consideration for the immobilisation of the UK civil PuO2 inventory. In the present work, a baseline dual-substituted zirconolite with the target composition (Ca0.783Gd0.017Ce0.2)(Zr0.883Gd0.017Ce0.1)(Ti1.6Al0.4)O7 was fabricated by hot isostatic pressing (HIPing). In order to optimise the microstructure properties and improve the obtained yield of the zirconolite phase, a range of planetary ball milling parameters were investigated prior to consolidation by HIP. This included milling the batched oxide precursors at 400 rpm for up to 120 min, the pre-milling of CeO2 (PuO2 surrogate) to reduce the particle size and using a CeO2 source with finer particle size (<5 µm). The HIPed zirconolite product consisted of both zirconolite-2M and zirconolite-3T polytypes in varying proportions; however, an additional perovskite phase was obtained in varying quantities as a secondary phase. Ce L3-edge X-ray absorption spectroscopy was utilised to determine the Ce oxidation state. In this study, the ideal milling parameter for the fabrication of zirconolite waste forms was defined as 60 min at 400 rpm.
      Citation: Ceramics
      PubDate: 2023-03-11
      DOI: 10.3390/ceramics6010043
      Issue No: Vol. 6, No. 1 (2023)
  • Ceramics, Vol. 6, Pages 717-733: Affect of the Scattering Asymmetry by
           Structural Element of Thermal- or Environmental-Barrier Ceramics on
           Subsurface Radiant Overheating

    • Authors: Vladimir Merzlikin, Evgeny Safonov, Andrey Kostyukov, Svetlana Parshina, Anna Dokukina
      First page: 717
      Abstract: The problem of the formation and estimation of a thermoradiant and temperature field in ceramics Thermal- Environmental-Barrier Coatings (TBC/EBC) has been considered with complex heat transfer but under the influence of the penetrating intense radiant component. The authors proposed to analyze not only TBC but also EBC from the point of view of the optics of semitransparent scattering and absorbing media in the range of ~0.4–4 μm of external radiant action. This paradigm allows us to continue the study of ceramic fibers embedded in ceramic matrix CMCs (C/C, C/SiC, SiC/SiC) as a traditional class of opaque materials. However, at the same time, mullites, Al2O3/Al2O3 have been reviewed as a class of semitransparent elements for designing CMCs. The relevance of studying the effect of oriented fibers on the formation of thermoradiation and temperature fields in a semitransparent material was noted. Modeling the scattering asymmetry coefficient influence (scattering phase function) on the generation of the subsurface thermal radiation source was carried out. The methodology for calculating the thermoradiative field in a semitransparent medium (with relative absorption, scattering indexes, and scattering asymmetry coefficient) was used under a one-dimensional two-flux model as the first approximation for solving the radiative heat transfer equation. Calculations of temperature profiles in opaque and semitransparent ceramics were presented under heat load typical for the combustion chambers operating regime of diesel and gas turbine engines.
      Citation: Ceramics
      PubDate: 2023-03-13
      DOI: 10.3390/ceramics6010044
      Issue No: Vol. 6, No. 1 (2023)
  • Ceramics, Vol. 6, Pages 734-797: Laboratory, Clinical-Related Processing
           and Time-Related Factors’ Effect on Properties of High Translucent
           Zirconium Dioxide Ceramics Intended for Monolithic Restorations a
           Systematic Review

    • Authors: Camilla Johansson, Sebastian Franco Tabares, Christel Larsson, Evaggelia Papia
      First page: 734
      Abstract: Because new zirconia materials are constantly being developed, the aim was to identify and qualitatively synthesize research on how processing and time-related factors affect the properties of high translucent (HT) zirconia intended for monolithic restorations. Cochrane Library, PubMed, Scopus, Web of Science, and reference lists were searched for in vitro and clinical studies. Eligibility and risk of bias were assessed. A synthesis of 142 publications was performed. HT 3Y-TZP was the most common, followed by 5YSZ, 4YSZ, and multilayer. In the laboratory, HT 3Y-TZP should be sintered according to the manufacturer’s recommendation and polished before glazing to favour strength, roughness, and wear behaviour. In the clinic, polishing is necessary after grinding to favour roughness and aging resistance. Over time, when using hydrothermal aging, t–m phase transformation and reduced translucency are expected, without affecting the strength and roughness. The strength of 4YSZ and 5YSZ is unaffected. However, the time-related methods are of questionable clinical significance. The evidence of all other factors’ effects on the properties of HT zirconia is lacking or limited; thus, these factors are of relevance for future research. There is a high heterogeneity of study designs and methods, and the results are brand-dependent.
      Citation: Ceramics
      PubDate: 2023-03-16
      DOI: 10.3390/ceramics6010045
      Issue No: Vol. 6, No. 1 (2023)
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Heriot-Watt University
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