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  Subjects -> ENGINEERING (Total: 2266 journals)
    - CHEMICAL ENGINEERING (190 journals)
    - CIVIL ENGINEERING (183 journals)
    - ELECTRICAL ENGINEERING (99 journals)
    - ENGINEERING (1195 journals)
    - ENGINEERING MECHANICS AND MATERIALS (391 journals)
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ENGINEERING (1195 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Full-text available via subscription   (Followers: 5)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 216)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 1)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 10)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 4)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 6)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 18)
Advances in Artificial Neural Systems     Open Access   (Followers: 3)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 14)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 18)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 13)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 35)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 29)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 5)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 6)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 7)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 4)
Applied Sciences     Open Access   (Followers: 3)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 8)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 2)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 7)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
Batteries     Open Access   (Followers: 3)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 3)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 9)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 1)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Full-text available via subscription   (Followers: 13)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 40)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 7)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 5)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 4)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 4)
Coatings     Open Access   (Followers: 2)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 23)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 252)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 177)
Composites Part B : Engineering     Hybrid Journal   (Followers: 223)
Composites Science and Technology     Hybrid Journal   (Followers: 164)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 12)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 25)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 8)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 25)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 7)
Control Engineering Practice     Hybrid Journal   (Followers: 40)
Control Theory and Informatics     Open Access   (Followers: 7)
Corrosion Science     Hybrid Journal   (Followers: 24)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)

        1 2 3 4 5 6 | Last

Journal Cover Coatings
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   ISSN (Online) 2079-6412
   Published by MDPI Homepage  [148 journals]
  • Coatings, Vol. 7, Pages 46: Internally Oxidized Ru–Zr Multilayer
           Coatings

    • Authors: Yung-I Chen, Tso-Shen Lu, Zhi-Ting Zheng
      First page: 46
      Abstract: In this study, equiatomic Ru–Zr coatings were deposited on Si wafers at 400 °C by using direct current magnetron cosputtering. The plasma focused on the circular track of the substrate holder and the substrate holder rotated at speeds within 1–30 rpm, resulting in cyclical gradient concentration in the growth direction. The nanoindentation hardness levels of the as-deposited Ru–Zr coatings increased as the stacking periods of the cyclical gradient concentration decreased. After the coatings were annealed in a 1% O2–99% Ar atmosphere at 600 °C for 30 min, the internally oxidized coatings shifted their respective structures to a laminated structure, misaligned laminated structure, and nanocomposite, depending on their stacking periods. The effects of the stacking period of the cyclical gradient concentration on the mechanical properties and structural evolution of the annealed Ru–Zr coatings were investigated in this study.
      PubDate: 2017-03-23
      DOI: 10.3390/coatings7040046
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 47: Fabrication and Characterization of
           AlxCoFeNiCu1−x High Entropy Alloys by Laser Metal Deposition

    • Authors: Xueyang Chen, Lei Yan, Sreekar Karnati, Yunlu Zhang, Frank Liou
      First page: 47
      Abstract: High entropy alloys are multicomponent alloys that have at least five different principal elements as alloying elements. Each of these elements has an atomic percentage between 5% and 35%. Typically, they form body-centered cubic (bcc) or face-centered cubic (fcc) structure and are known to possess excellent mechanical properties, corrosion resistance, excellent electric and magnetic properties. Owing to their excellent corrosion and wear resistance, researchers are focusing on employing these materials as coatings. In this research, Laser Metal Deposition (LMD) was used to fabricate AlxCoFeNiCu1−x (x = 0.25, 0.5, 0.75) high entropy alloys from elemental powder based feedstocks. Thin wall claddings fabricated via LMD were characterized by a variety of techniques. Data from X-ray Diffraction (XRD) and Electron Back Scatter Diffraction (EBSD) suggested that with increase in Al content and decrease in Cu content, a change in crystal structure from a predominantly fcc to a combined fcc and bcc structure can be observed. The microstructure of the material was observed to be columnar dendritic. Data from standard less EDS analysis showed that the dendritic phase was Fe and Co enriched while the matrix was Cu and Al enriched in all the considered high entropy alloy fabrications. The Vickers hardness data was used to estimate the mechanical properties of these deposits. Results also showed that with the increase in aluminum content, AlxCoFeNiCu1−x displayed higher hardness. The high hardness values imply potential applications in wear resistant coatings.
      PubDate: 2017-03-25
      DOI: 10.3390/coatings7040047
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 48: Statistical Determination of a
           Fretting-Induced Failure of an Electro-Deposited Coating

    • Authors: Kyungmok Kim
      First page: 48
      Abstract: This paper describes statistical determination of fretting-induced failure of an electro-deposited coating. A fretting test is conducted using a ball-on-flat plate configuration. During a test, a frictional force is measured, along with the relative displacement between an AISI52100 ball and a coated flat specimen. Measured data are analyzed with statistical process control tools; a frictional force versus number of fretting cycles is plotted on a control chart. On the control chart, critical number of cycles to coating failure is statistically determined. Fretted surfaces are observed after interrupting a series of fretting tests. Worn surface images and wear profiles provide that the increase on the kinetic friction coefficient after a steady-state sliding is attributed to the substrate enlarged at a contact surface. There is a good agreement between observation of worn surfaces and statistical determination for fretting-induced coating failure.
      PubDate: 2017-03-31
      DOI: 10.3390/coatings7040048
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 49: Hybrid Metaheuristic-Neural Assessment of the
           Adhesion in Existing Cement Composites

    • Authors: Łukasz Sadowski, Mehdi Nikoo, Mohammad Nikoo
      First page: 49
      Abstract: The article presents the hybrid metaheuristic-neural assessment of the pull-off adhesion in existing multi-layer cement composites using artificial neural networks (ANNs) and the imperialist competitive algorithm (ICA). The ICA is a metaheuristic algorithm inspired by the human political-social evolution. This method is based solely on the use of ANNs and two non-destructive testing (NDT) methods: the impact-echo method (I-E) and the impulse response method (IR). In this research, the ICA has been used to optimize the weights of the ANN. The combined ICA-ANN model has been compared to the genetic algorithm (GA) and particle swarm optimization (PSO) to evaluate its accuracy. The results showed that the ICA-ANN model outperforms other techniques when testing datasets in terms of both effectiveness and efficiency. As presented in the validation stage, it is possible to reliably map the adhesion level on a tested surface without local damage to the latter.
      PubDate: 2017-04-01
      DOI: 10.3390/coatings7040049
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 50: Studies on the Effect of Arc Current Mode and
           Substrate Rotation Configuration on the Structure and Corrosion Behavior
           of PVD TiN Coatings

    • Authors: Liam Ward, Antony Pilkington, Steve Dowey
      First page: 50
      Abstract: Thin, hard cathodic arc evaporated (CAE) metal nitride coatings are known to contain defects such as macro-particles, pinholes, voids and increased porosity, leading to reduced corrosion resistance. The focus of this research investigation was to compare the structure and corrosion behaviour of cathodic arc evaporated (CAE) TiN coatings deposited on AISI 1020 low carbon steel substrates using a pulsed current arc and a more conventional constant current arc source (DC). The effects of a double (2R) and triple (3R) substrate rotation configuration were also studied. Coating morphology and chemical composition were characterised using optical, SEM imaging and XRD analysis. Focus variation microscopy (FVM), an optical 3D measurement technique, was used to measure surface roughness. Corrosion studies were carried out using potentiodynamic scanning in 3.5% NaCl. Tafel extrapolation was carried out to determine Ecorr and Icorr values for the coated samples. In general, increased surface roughness, and to a certain extent, corrosion resistance, were associated with thicker coatings deposited using 2R, compared to 3R rotation configuration. The arc source mode (continuous or pulsed) was shown to have little effect on the corrosion behavior. Corrosion behavior was controlled by the presence of defects, pinholes and macro-particles at lower anodic potentials, while the formation of large pitted regions and aggressive corrosion of the underlying substrate was observed at higher anodic potentials.
      PubDate: 2017-04-04
      DOI: 10.3390/coatings7040050
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 51: Effect on Concrete Surface Water Absorption
           upon Addition of Lactate Derived Agent

    • Authors: Renee Mors, Henk Jonkers
      First page: 51
      Abstract: Water tightness of a concrete cover layer is important, as it is typically used as a protective coating of the steel reinforcement. Water tightness can be impaired by crack formation or by permeability. A bacteria-based lactate-derived healing agent (HA) can be added to concrete to enhance the potential for restoration of water tightness. Bacterial conversion of the included carbon source results in CO2 production and subsequent CaCO3 precipitation, similar to the mechanism of concrete carbonation. Carbonation is known to densify concrete, particularly when using ordinary Portland cement (OPC), but to a much lower extend in slag-based concrete (CEM III/B). To identify the effect of HA addition on concrete properties, this study focusses on the ingress of moisture in non-cracked concrete surfaces by assessing capillary water absorption. Surface properties were determined for sealed and unsealed surfaces of concrete—either based on OPC or CEM III/B—before and after curing under three different conditions: Dry, wet, or humid. HA addition to concrete containing slag cement generated a surface less prone to continued drying, but resulted in higher water absorption. In contrast, surface water absorption significantly decreased upon HA addition to OPC-based samples, independent of the curing regime. It is therefore concluded that HA in its current form is suitable for application in OPC, but less in CEM III/B-based mixtures.
      PubDate: 2017-04-07
      DOI: 10.3390/coatings7040051
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 52: The Effect of Temperature and Local pH on
           Calcareous Deposit Formation in Damaged Thermal Spray Aluminum (TSA)
           Coatings and Its Implication on Corrosion Mitigation of Offshore Steel
           Structures

    • Authors: Nataly Ce, Shiladitya Paul
      First page: 52
      Abstract: This paper is based on experimental data and provides better understanding of the mechanism of calcareous deposit formation on cathodically polarized steel surfaces exposed to synthetic seawater at 30 °C and 60 °C. The study comprises measurement of the interfacial pH of thermally sprayed aluminum (TSA) coated steel samples with and without a holiday (exposing 20% of the surface area). Tests were conducted at the corrosion potential for up to 350 h. It was experimentally determined that the local pH adjacent to the steel surface in the holiday region reached a maximum of 10.19 and 9.54 at 30 °C and 60 °C, respectively, before stabilizing at about 8.8 and 7.9 at the two temperatures. The interfacial pH on the TSA coating at 30 °C was initially 7.74 dropping to 4.76 in 220 h, while at 60 °C it increased from pH 6.41 to the range pH 7.0–8.5. The interfacial pH governed the deposition of brucite and aragonite from seawater on the steel surface cathodically polarized by the TSA. This mechanism is likely to affect the performance of TSA-coated offshore steel structures, especially when damaged in service.
      PubDate: 2017-04-11
      DOI: 10.3390/coatings7040052
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 53: Preparation of Metal Coatings on Steel Balls
           Using Mechanical Coating Technique and Its Process Analysis

    • Authors: Liang Hao, Hiroyuki Yoshida, Takaomi Itoi, Yun Lu
      First page: 53
      Abstract: We successfully applied mechanical coating technique to prepare Ti coatings on the substrates of steel balls and stainless steel balls. The prepared samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The weight increase of the ball substrates and the average thickness of Ti coatings were also monitored. The results show that continuous Ti coatings were prepared at different revolution speeds after different durations. Higher revolution speed can accelerate the formation of continuous Ti coatings. Substrate hardness also markedly affected the formation of Ti coatings. Specifically, the substance with lower surface hardness was more suitable as the substrate on which to prepare Ti coatings. The substrate material plays a key role in the formation of Ti coatings. Specifically, Ti coatings formed more easily on metal/alloy balls than ceramic balls. The above conclusion can also be applied to other metal or alloy coatings on metal/alloy and ceramic substrates.
      PubDate: 2017-04-10
      DOI: 10.3390/coatings7040053
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 54: Erosion Wear Investigation of HVOF Sprayed
           WC-10Co4Cr Coating on Slurry Pipeline Materials

    • Authors: Kaushal Kumar, Satish Kumar, Gurprit Singh, Jatinder Singh, Jashanpreet Singh
      First page: 54
      Abstract: In the present work, erosion wear due to slurry mixture flow has been investigated using a slurry erosion pot tester. Erosion tests are conducted on three different slurry pipe materials, namely, mild steel, SS202, and SS304, to establish the influence of rotational speed, concentration, and time period. In order to increase erosion wear resistance, a high-velocity oxy-fuel (HVOF) coating technique is used to deposit a WC-10Co4Cr coating on the surface of all piping materials. Experimental results show that rotational speed is a highly-influencing parameter for the erosion wear rate as compared to solid concentration, time duration, and weighted mean diameter. WC-10Co4Cr HVOF coating improved the erosion resistance of piping materials up to 3.5 times. From experimental data, the exponents of solid concentration, velocity, and the size of particles are calculated for the empirical erosion wear equation. A functional equation of the erosion wear rate is developed. The predicted erosion wear is in agreement with the experimental data and found to be within a deviation of ±12%.
      PubDate: 2017-04-12
      DOI: 10.3390/coatings7040054
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 55: Application of High-Velocity Oxygen-Fuel
           (HVOF) Spraying to the Fabrication of Yb-Silicate Environmental Barrier
           Coatings

    • Authors: Emine Bakan, Georg Mauer, Yoo Sohn, Dietmar Koch, Robert Vaßen
      First page: 55
      Abstract: From the literature, it is known that due to their glass formation tendency, it is not possible to deposit fully-crystalline silicate coatings when the conventional atmospheric plasma spraying (APS) process is employed. In APS, rapid quenching of the sprayed material on the substrate facilitates the amorphous deposit formation, which shrinks when exposed to heat and forms pores and/or cracks. This paper explores the feasibility of using a high-velocity oxygen-fuel (HVOF) process for the cost-effective fabrication of dense, stoichiometric, and crystalline Yb2Si2O7 environmental barrier coatings. We report our findings on the HVOF process optimization and its resultant influence on the microstructure development and crystallinity of the Yb2Si2O7 coatings. The results reveal that partially crystalline, dense, and vertical crack-free EBCs can be produced by the HVOF technique. However, the furnace thermal cycling results revealed that the bonding of the Yb2Si2O7 layer to the Silicon bond coat needs to be improved.
      PubDate: 2017-04-18
      DOI: 10.3390/coatings7040055
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 56: State of the Art of Antimicrobial Edible
           Coatings for Food Packaging Applications

    • Authors: Arantzazu Valdés, Marina Ramos, Ana Beltrán, Alfonso Jiménez, María Garrigós
      First page: 56
      Abstract: The interest for the development of new active packaging materials has rapidly increased in the last few years. Antimicrobial active packaging is a potential alternative to protect perishable products during their preparation, storage and distribution to increase their shelf-life by reducing bacterial and fungal growth. This review underlines the most recent trends in the use of new edible coatings enriched with antimicrobial agents to reduce the growth of different microorganisms, such as Gram-negative and Gram-positive bacteria, molds and yeasts. The application of edible biopolymers directly extracted from biomass (proteins, lipids and polysaccharides) or their combinations, by themselves or enriched with natural extracts, essential oils, bacteriocins, metals or enzyme systems, such as lactoperoxidase, have shown interesting properties to reduce the contamination and decomposition of perishable food products, mainly fish, meat, fruits and vegetables. These formulations can be also applied to food products to control gas exchange, moisture permeation and oxidation processes.
      PubDate: 2017-04-19
      DOI: 10.3390/coatings7040056
      Issue No: Vol. 7, No. 4 (2017)
       
  • Coatings, Vol. 7, Pages 35: Pitted Corrosion Detection of Thermal Sprayed
           Metallic Coatings Using Fiber Bragg Grating Sensors

    • Authors: Fodan Deng, Ying Huang, Fardad Azarmi, Yechun Wang
      First page: 35
      Abstract: Metallic coatings using thermal spraying techniques are widely applied to structural steels to protect infrastructure against corrosion and improve durability of the associated structures for longer service life. The thermal sprayed metallic coatings consisting of various metals, although have higher corrosion resistance, will still corrode in a long run and may also subject to corrosion induced damages such as cracks. Corrosion and the induced damages on the metallic coatings will reduce the effectiveness of the coatings for protection of the structures. Timely repair on these damaged metallic coatings will significantly improve the reliability of protected structures again deterioration. In this paper, an inline detection system for corrosion and crack detection was developed using fiber Bragg (FBG) grating sensors. Experimental results from laboratory accelerated corrosion tests showed that the developed sensing system can quantitatively detect corrosion rate of the coating, corrosion propagations, and cracks initialized in the metallic coating in real time. The developed system can be used for real-time corrosion detection of coated metal structures in field.
      PubDate: 2017-02-24
      DOI: 10.3390/coatings7030035
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 36: Effect of Electrochemically Deposited MgO
           Coating on Printable Perovskite Solar Cell Performance

    • Authors: T. A. Peiris, Ajay Baranwal, Hiroyuki Kanda, Shouta Fukumoto, Shusaku Kanaya, Takeru Bessho, Ludmila Cojocaru, Tsutomu Miyasaka, Hiroshi Segawa, Seigo Ito
      First page: 36
      Abstract: Herein, we studied the effect of MgO coating thickness on the performance of printable perovskite solar cells (PSCs) by varying the electrodeposition time of Mg(OH)2 on the fluorine-doped tin oxide (FTO)/TiO2 electrode. Electrodeposited Mg(OH)2 in the electrode was confirmed by energy dispersive X-ray (EDX) analysis and scanning electron microscopic (SEM) images. The performance of printable PSC structures on different deposition times of Mg(OH)2 was evaluated on the basis of their photocurrent density-voltage characteristics. The overall results confirmed that the insulating MgO coating has an adverse effect on the photovoltaic performance of the solid state printable PSCs. However, a marginal improvement in the device efficiency was obtained for the device made with the 30 s electrodeposited TiO2 electrode. We believe that this undesirable effect on the photovoltaic performance of the printable PSCs is due to the higher coverage of TiO2 by the insulating MgO layer attained by the electrodeposition technique.
      PubDate: 2017-02-27
      DOI: 10.3390/coatings7030036
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 37: Investigation of Coating Performance of
           UV-Curable Hybrid Polymers Containing
           1H,1H,2H,2H-Perfluorooctyltriethoxysilane Coated on Aluminum Substrates

    • Authors: Mustafa Çakır
      First page: 37
      Abstract: This study describes preparation and characterization of fluorine-containing organic-inorganic hybrid coatings. The organic part consists of bisphenol-A glycerolate (1 glycerol/phenol) diacrylate resin and 1,6-hexanediol diacrylate reactive diluent. The inorganically rich part comprises trimethoxysilane-terminated urethane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 3-(trimethoxysilyl) propyl methacrylate and sol–gel precursors that are products of hydrolysis and condensation reactions. Bisphenol-A glycerolate (1 glycerol/phenol) diacrylate resin was added to the inorganic part in predetermined amounts. The resultant mixture was utilized in the preparation of free films as well as coatings on aluminum substrates. Thermal and mechanical tests such as DSC, thermo-gravimetric analysis (TGA), and tensile and shore D hardness tests were performed on free films. Water contact angle, gloss, Taber abrasion test, cross-cut and tubular impact tests were conducted on the coated samples. SEM examination and EDS analysis was performed on the fractured surfaces of free films. The hybrid coatings on the aluminum sheets gave rise to properties such as moderately glossed surface; low wear rate and hydrophobicity. Tensile strength of free films increased with up to 10% inorganic content in the hybrid structure and this increase was approximately three times that of the control sample. As expected; the % strain value decreased by 17.3 with the increase in inorganic content and elastic modulus values increased by a factor of approximately 6. Resistance to ketone-based solvents was proven and an increase in hardness was observed as the ratio of the inorganic part increased. Samples which contain 10% sol–gel content were observed to provide optimal properties.
      PubDate: 2017-03-02
      DOI: 10.3390/coatings7030037
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 38: A Field Performance Evaluation Scheme for
           Microwave-Absorbing Material Coatings

    • Authors: Shaopeng Guan, Yongyu Wang, Daiping Jia
      First page: 38
      Abstract: Performance evaluation is an important aspect in the study of microwave-absorbing material coatings. The reflectivity of the incident wave is usually taken as the performance indicator. There have been various methods to directly or indirectly measure the reflectivity, but existing methods are mostly cumbersome and require a strict testing environment. What is more, they cannot be applied to field measurement. In this paper, we propose a scheme to achieve field performance evaluation of microwave-absorbing materials, which adopts a small H-plane sectoral horn antenna as the testing probe and a small microwave reflectometer as the indicator. When the size of the H-plane sectoral horn antenna is specially designed, the field distribution at the antenna aperture can be approximated as a plane wave similar to the far field of the microwave emitted by a radar unit. Therefore, the reflectivity can be obtained by a near-field measurement. We conducted experiments on a kind of ferrite-based microwave-absorbing material at X band (8.2–12.4 GHz) to validate the scheme. The experimental results show that the reflectivity is in agreement with the reference data measured by the conventional method as a whole.
      PubDate: 2017-03-02
      DOI: 10.3390/coatings7030038
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 39: Influence of the Electrolyte Concentration on
           the Smooth TiO2 Anodic Coatings on Ti-6Al-4V

    • Authors: María Vera, Ángeles Colaccio, Mario Rosenberger, Carlos Schvezov, Alicia Ares
      First page: 39
      Abstract: To obtain smooth TiO2 coatings for building a new design of Ti-6Al-4V heart valve, the anodic oxidation technique in pre-spark conditions was evaluated. TiO2 coating is necessary for its recognized biocompatibility and corrosion resistance. A required feature on surfaces in contact with blood is a low level of roughness (Ra ≤ 50 nm) that does not favor the formation of blood clots. The present paper compares the coatings obtained by anodic oxidation of the Ti-6Al-4V alloy using H2SO4 at different concentrations (0.1–4 M) as electrolyte and applying different voltages (from 20 to 70 V). Color and morphological analysis of coatings are performed using optical and scanning microscopy. The crystalline phases were analyzed by glancing X-ray diffraction. By varying the applied voltage, different interference colors coatings were obtained. The differences in morphologies of the coatings caused by changes in acid concentration are more evident at high voltages, limiting the oxidation conditions for the desired application. Anatase phase was detected from 70 V for 1 M H2SO4. An increase in the concentration of H2SO4 decreases the voltage at which the transformation of amorphous to crystalline coatings occurs; i.e., with 4 M H2SO4, the anatase phase appears at 60 V.
      PubDate: 2017-03-03
      DOI: 10.3390/coatings7030039
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 40: Development of a Fabrication Process Using
           Suspension Plasma Spray for Titanium Oxide Photovoltaic Device

    • Authors: Hsian Sagr Hadi A, Yasutaka Ando
      First page: 40
      Abstract: In order to reduce the high costs of conventional materials, and to reduce the power necessary for the deposition of titanium dioxide, titanium tetrabutoxide has been developed in the form of a suspension of TiO2 using water instead of expensive ethanol. To avoid sedimentation of hydroxide particles in the suspension, mechanical milling of the suspension was conducted in order to create diffusion in colloidal suspension before using it as feedstock. Consequently, through the creation of a colloidal suspension, coating deposition was able to be conducted without sedimentation of the hydroxide particles in the suspension during the deposition process. Though an amorphous as-deposited coating was able to be deposited, through post heat treatment at 630 °C for 60 min, the chemical structure became anatase rich. In addition, it was confirmed that the post heat treated anatase rich coating had enough photo-catalytic activity to decolor methylene-blue droplets. From these results, this technique was found to have high potential in the low cost photo-catalytic titanium coating production process.
      PubDate: 2017-03-04
      DOI: 10.3390/coatings7030040
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 41: Ozone Resistance, Water Permeability, and
           Concrete Adhesion of Metallic Films Sprayed on a Concrete Structure for
           Advanced Water Purification

    • Authors: Jin-Ho Park, Jitendra Singh, Han-Seung Lee
      First page: 41
      Abstract: We evaluated the applicability of metal spray coating as a waterproofing/corrosion protection method for a concrete structure used for water purification. We carried out an ozone resistance test on four metal sprays and evaluated the water permeability and bond strength of the metals with superior ozone resistance, depending on the surface treatment method. In the ozone resistance test, four metal sprays and an existing ozone-proof paint were considered. In the experiment on the water permeability and bond strength depending on the surface treatment method, the methods of no treatment, surface polishing, and two types of pore sealing agents were considered. The results showed that the sprayed titanium had the best ozone resistance. Applying a pore sealing agent provided the best adhesion performance, of about 3.2 MPa. Applying a pore sealing agent also provided the best waterproofing performance. Scanning electron microscope analysis showed that applying a pore sealing agent resulted in an excellent waterproofing performance because a coating film formed on top of the metal spray coating. Thus, when using a metal spray as waterproofing/corrosion protection for a water treatment concrete structure, applying a pore sealing agent on top of a film formed by spraying titanium was concluded to be the most appropriate method.
      PubDate: 2017-03-10
      DOI: 10.3390/coatings7030041
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 42: Defect-Free Large-Area (25 cm2) Light
           Absorbing Perovskite Thin Films Made by Spray Coating

    • Authors: Mehran Habibi, Amin Rahimzadeh, Inas Bennouna, Morteza Eslamian
      First page: 42
      Abstract: In this work, we report on reproducible fabrication of defect-free large-area mixed halide perovskite (CH3NH3PbI3−xClx) thin films by scalable spray coating with the area of 25 cm2. This is essential for the commercialization of the perovskite solar cell technology. Using an automated spray coater, the film thickness and roughness were optimized by controlling the solution concentration and substrate temperature. For the first time, the surface tension, contact angle, and viscosity of mixed halide perovskite dissolved in dimethylformamide (DMF) are reported as a function of the solution concentration. A low perovskite solution concentration of 10% was selected as an acceptable value to avoid crystallization dewetting. The determined optimum substrate temperature of 150 °C, followed by annealing at 100 °C render the highest perovskite precursor conversion, as well as the highest possible droplet spreading, desired to achieve a continuous thin film. The number of spray passes was also tuned to achieve a fully-covered film, for the condition of the spray nozzle used in this work. This work demonstrates that applying the optimum substrate temperature decreases the standard deviation of the film thickness and roughness, leading to an increase in the quality and reproducibility of the large-area spray-on films. The optimum perovskite solution concentration and the substrate temperature are universally applicable to other spray coating systems.
      PubDate: 2017-03-12
      DOI: 10.3390/coatings7030042
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 43: Investigation of a Simplified Mechanism Model
           for Prediction of Gallium Nitride Thin Film Growth through Numerical
           Analysis

    • Authors: Chih-Kai Hu, Chun-Jung Chen, Ta-Chin Wei, Tomi Li, Ching-Chiun Wang, Chih-Yung Huang
      First page: 43
      Abstract: A numerical procedure was performed to simplify the complicated mechanism of an epitaxial thin-film growth process. In this study, three numerical mechanism models are presented for verifying the growth rate of the gallium nitride (GaN) mechanism. The mechanism models were developed through rate of production analysis. All of the results can be compared in one schematic diagram, and the differences among these three mechanisms are pronounced at high temperatures. The simplified reaction mechanisms were then used as input for a two-dimensional computational fluid dynamics code FLUENT, enabling the accurate prediction of growth rates. Validation studies are presented for two types of laboratory-scale reactors (vertical and horizontal). A computational study including thermal and flow field was also performed to investigate the fluid dynamic in those reactors. For each study, the predictions agree acceptably well with the experimental data, indicating the reasonable accuracy of the reaction mechanisms.
      PubDate: 2017-03-15
      DOI: 10.3390/coatings7030043
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 44: High-Temperature Corrosion of AlCrSiN Film in
           Ar-1%SO2 Gas

    • Authors: Poonam Yadav, Dong Lee, Yue Lin, Shihong Zhang, Sik Kwon
      First page: 44
      Abstract: AlCrSiN film with a composition of 29.1Al-17.1Cr-2.1Si-51.7N in at. % was deposited on a steel substrate by cathodic arc ion plating at a thickness of 1.8 μm. It consisted of nanocrystalline hcp-AlN and fcc-CrN, where a small amount of Si was dissolved. Corrosion tests were carried out at 800 °C for 5–200 h in Ar-1%SO2 gas. The major corrosion reaction was oxidation owing to the high oxygen affinity of Al and Cr in the film. The formed oxide scale consisted primarily of (Al,Cr)2O3, within which Fe, Si, and S were dissolved. Even after corrosion for 200 h, the thickness of the scale was about 0.7–1.2 μm, indicating that the film had good corrosion resistance in the SO2-containing atmosphere.
      PubDate: 2017-03-13
      DOI: 10.3390/coatings7030044
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 45: Review of Antibacterial Activity of
           Titanium-Based Implants’ Surfaces Fabricated by Micro-Arc Oxidation

    • Authors: Xiaojing He, Xiangyu Zhang, Xin Wang, Lin Qin
      First page: 45
      Abstract: Ti and its alloys are the most commonly-used materials for biomedical applications. However, bacterial infection after implant placement is still one of the significant rising complications. Therefore, the application of the antimicrobial agents into implant surfaces to prevent implant-associated infection has attracted much attention. Scientific papers have shown that inorganic antibacterial metal elements (e.g., Ag, Cu, Zn) can be introduced into implant surfaces with the addition of metal nanoparticles or metallic compounds into an electrolyte via micro-arc oxidation (MAO) technology. In this review, the effects of the composition and concentration of electrolyte and process parameters (e.g., voltage, current density, oxidation time) on the morphological characteristics (e.g., surface morphology, bonding strength), antibacterial ability and biocompatibility of MAO antimicrobial coatings are discussed in detail. Anti-infection and osseointegration can be simultaneously accomplished with the selection of the proper antibacterial elements and operating parameters. Besides, MAO assisted by magnetron sputtering (MS) to endow Ti-based implant materials with superior antibacterial ability and biocompatibility is also discussed. Finally, the development trend of MAO technology in the future is forecasted.
      PubDate: 2017-03-22
      DOI: 10.3390/coatings7030045
      Issue No: Vol. 7, No. 3 (2017)
       
  • Coatings, Vol. 7, Pages 17: Electroplating of CdTe Thin Films from Cadmium
           Sulphate Precursor and Comparison of Layers Grown by 3-Electrode and
           2-Electrode Systems

    • Authors: Imyhamy Dharmadasa, Mohammad Madugu, Olajide Olusola, Obi Echendu, Fijay Fauzi, Dahiru Diso, Ajith Weerasinghe, Thad Druffel, Ruvini Dharmadasa, Brandon Lavery, Jacek Jasinski, Tatiana Krentsel, Gamini Sumanasekera
      First page: 17
      Abstract: Electrodeposition of CdTe thin films was carried out from the late 1970s using the cadmium sulphate precursor. The solar energy group at Sheffield Hallam University has carried out a comprehensive study of CdTe thin films electroplated using cadmium sulfate, cadmium nitrate and cadmium chloride precursors, in order to select the best electrolyte. Some of these results have been published elsewhere, and this manuscript presents the summary of the results obtained on CdTe layers grown from cadmium sulphate precursor. In addition, this research program has been exploring the ways of eliminating the reference electrode, since this is a possible source of detrimental impurities, such as K+ and Ag+ for CdS/CdTe solar cells. This paper compares the results obtained from CdTe layers grown by three-electrode (3E) and two-electrode (2E) systems for their material properties and performance in CdS/CdTe devices. Thin films were characterized using a wide range of analytical techniques for their structural, morphological, optical and electrical properties. These layers have also been used in device structures; glass/FTO/CdS/CdTe/Au and CdTe from both methods have produced solar cells to date with efficiencies in the region of 5%–13%. Comprehensive work carried out to date produced comparable and superior devices fabricated from materials grown using 2E system.
      PubDate: 2017-01-24
      DOI: 10.3390/coatings7020017
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 18: Influence of the Distribution of a Spray Paint
           on the Efficacy of Anti-Graffiti Coatings on a Highly Porous Natural Stone
           Material

    • Authors: Maurizio Masieri, Mariateresa Lettieri
      First page: 18
      Abstract: Graffiti on facades often has a heavy impact in social and economic terms, particularly when historical and artistic artefacts are affected. To limit the damages to the surfaces, preventive plans are implemented and anti-graffiti coatings are used as a protective measure. In this study, the distribution of a spray paint inside a highly porous stone, with and without anti-graffiti protection, was investigated. Two commercial sacrificial anti-graffiti systems were used and an acrylic-based paint was applied as staining agent. Environmental scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS) microanalysis were performed to characterise, from the morphological and chemical point of view, the anti-graffiti coatings and the paint. Maps of the main elements were acquired to locate the different products inside the stone. Chemical removers were used to clean the stained surfaces, then the effectiveness of the cleaning was assessed by visual observations and colour measurements, as well as on the basis of percentage of residual stain. The obtained results highlighted that the anti-graffiti efficacy strongly depended on the characteristics of the applied coating. This latter usually acted as a barrier, but good results were obtained only where the stain did not remain as a separate layer, but penetrated the protective coating. Microcracks in the anti-graffiti coating were able to nullify the protective action.
      PubDate: 2017-01-24
      DOI: 10.3390/coatings7020018
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 19: Fabrication of Efficient Cu2ZnSnS4 Solar Cells
           by Sputtering Single Stoichiometric Target

    • Authors: Hongtao Cui, Xiaolei Liu, Lingling Sun, Fangyang Liu, Chang Yan, Xiaojing Hao
      First page: 19
      Abstract: Low cost single stoichiometric target sputtering of Cu2ZnSnS4 (CZTS) precursor has been adopted to fabricate CZTS solar cells. The effect of a series of deposition pressures and deposition durations on the device performance has been investigated. A 3.74% efficient solar cell has been achieved at a base pressure of 1 × 10−4 Torr with a stoichiometric target, which to the authors’ knowledge, is the record efficiency for such a stoichiometric target.
      PubDate: 2017-01-24
      DOI: 10.3390/coatings7020019
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 20: Recent Developments in Accelerated
           Antibacterial Inactivation on 2D Cu-Titania Surfaces under Indoor Visible
           Light

    • Authors: Sami Rtimi, Cesar Pulgarin, John Kiwi
      First page: 20
      Abstract: This review focuses on Cu/TiO2 sequentially sputtered and Cu-TiO2 co-sputtered catalytic/photocatalytic surfaces that lead to bacterial inactivation, discussing their stability, synthesis, adhesion, and antibacterial kinetics. The intervention of TiO2, Cu, and the synergic effect of Cu and TiO2 on films prepared by a colloidal sol-gel method leading to bacterial inactivation is reviewed. Processes in aerobic and anaerobic media leading to bacterial loss of viability in multidrug resistant (MDR) pathogens, Gram-negative, and Gram-positive bacteria are described. Insight is provided for the interfacial charge transfer mechanism under solar irradiation occurring between TiO2 and Cu. Surface properties of 2D TiO2/Cu and TiO2-Cu films are correlated with the bacterial inactivation kinetics in dark and under light conditions. The intervention of these antibacterial sputtered surfaces in health-care facilities, leading to Methicillin-resistant Staphylococcus Aureus (MRSA)-isolates inactivation, is described in dark and under actinic light conditions. The synergic intervention of the Cu and TiO2 films leading to bacterial inactivation prepared by direct current magnetron sputtering (DCMS), pulsed direct current magnetron sputtering (DCMSP), and high power impulse magnetron sputtering (HIPIMS) is reported in a detailed manner.
      PubDate: 2017-02-06
      DOI: 10.3390/coatings7020020
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 21: Interfacial Mechanics Analysis of a Brittle
           Coating–Ductile Substrate System Involved in Thermoelastic Contact

    • Authors: Chi Zhang, Le Gu, Chongyang Nie, Chuanwei Zhang, Liqin Wang
      First page: 21
      Abstract: In this paper, interfacial stress analysis for a brittle coating/ductile substrate system, which is involved in a sliding contact with a rigid ball, is presented. By combining interface mechanics theory and the image point method, stress and displacement responses within a coated material for normal load, tangential load, and thermal load are obtained; further, the Green’s functions are established. The effects of coating thickness, friction coefficient, and a coating’s thermoelastic properties on the interfacial shear stress, τxz, and transverse stress, σxx, distributions are discussed in detail. A phenomenon, where interfacial shear stress tends to be relieved by frictional heating, is found in the case of a coating material’s thermal expansion coefficient being less than a substrate material’s thermal expansion coefficient. Additionally, numerical results show that distribution of interfacial stress can be altered and, therefore, interfacial damage can be modified by adjusting a coating’s structural parameters and thermoelastic properties.
      PubDate: 2017-02-06
      DOI: 10.3390/coatings7020021
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 22: Multiscale Computational Fluid Dynamics:
           Methodology and Application to PECVD of Thin Film Solar Cells

    • Authors: Marquis Crose, Anh Tran, Panagiotis Christofides
      First page: 22
      Abstract: This work focuses on the development of a multiscale computational fluid dynamics (CFD) simulation framework with application to plasma-enhanced chemical vapor deposition of thin film solar cells. A macroscopic, CFD model is proposed which is capable of accurately reproducing plasma chemistry and transport phenomena within a 2D axisymmetric reactor geometry. Additionally, the complex interactions that take place on the surface of a-Si:H thin films are coupled with the CFD simulation using a novel kinetic Monte Carlo scheme which describes the thin film growth, leading to a multiscale CFD model. Due to the significant computational challenges imposed by this multiscale CFD model, a parallel computation strategy is presented which allows for reduced processing time via the discretization of both the gas-phase mesh and microscopic thin film growth processes. Finally, the multiscale CFD model has been applied to the PECVD process at industrially relevant operating conditions revealing non-uniformities greater than 20% in the growth rate of amorphous silicon films across the radius of the wafer.
      PubDate: 2017-02-08
      DOI: 10.3390/coatings7020022
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 23: Silicides and Nitrides Formation in Ti Films
           Coated on Si and Exposed to (Ar-N2-H2) Expanding Plasma

    • Authors: Isabelle Jauberteau, Richard Mayet, Julie Cornette, Denis Mangin, Annie Bessaudou, Pierre Carles, Jean Jauberteau, Armand Passelergue
      First page: 23
      Abstract: The physical properties including the mechanical, optical and electrical properties of Ti nitrides and silicides are very attractive for many applications such as protective coatings, barriers of diffusion, interconnects and so on. The simultaneous formation of nitrides and silicides in Ti films improves their electrical properties. Ti films coated on Si wafers are heated at various temperatures and processed in expanding microwave (Ar-N2-H2) plasma for various treatment durations. The Ti-Si interface is the centre of Si diffusion into the Ti lattice and the formation of various Ti silicides, while the Ti surface is the centre of N diffusion into the Ti film and the formation of Ti nitrides. The growth of silicides and nitrides gives rise to two competing processes which are thermodynamically and kinetically controlled. The effect of thickness on the kinetics of the formation of silicides is identified. The metastable C49TiSi2 phase is the main precursor of the stable C54TiSi2 phase, which crystallizes at about 600 °C, while TiN crystallizes at about 800 °C.
      PubDate: 2017-02-08
      DOI: 10.3390/coatings7020023
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 24: Using an Atmospheric Pressure Chemical Vapor
           Deposition Process for the Development of V2O5 as an Electrochromic
           Material

    • Authors: Dimitra Vernardou
      First page: 24
      Abstract: Vanadium pentoxide coatings were grown by atmospheric pressure chemical vapor deposition varying the gas precursor ratio (vanadium (IV) chloride:water) and the substrate temperature. All samples were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, cyclic voltammetry, and transmittance measurements. The water flow rate was found to affect the crystallinity and the morphological characteristics of vanadium pentoxide. Dense stacks of long grains of crystalline oxide are formed at the highest amount of water utilized for a substrate temperature of 450 °C. Accordingly, it was indicated that for higher temperatures and a constant gas precursor ratio of 1:7, the surface morphology becomes flattened, and columnar grains of uniform size and shape are indicated, keeping the high crystalline quality of the material. Hence, it was possible to define a frame of operating parameters wherein single-phase vanadium pentoxide may be reliably expected, including a gas precursor ratio of 1:7 with a substrate temperature of >450 °C. The as-grown vanadium pentoxide at 550 °C for a gas precursor ratio of 1:7 presented the best electrochemical performance, including a diffusion coefficient of 9.19 × 10−11 cm2·s−1, a charge density of 3.1 mC·cm−2, and a coloration efficiency of 336 cm2·C−1. One may then say that this route can be important for the growth of large-scale electrodes with good performance for electrochromic devices.
      PubDate: 2017-02-08
      DOI: 10.3390/coatings7020024
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 25: Corrosion Protection Systems and Fatigue
           Corrosion in Offshore Wind Structures: Current Status and Future
           Perspectives

    • Authors: Seth Price, Rita Figueira
      First page: 25
      Abstract: Concerns over reducing CO2 emissions associated with the burning of fossil fuels in combination with an increase in worldwide energy demands is leading to increased development of renewable energies such as wind. The installation of offshore wind power structures (OWS) is one of the most promising approaches for the production of renewable energy. However, corrosion and fatigue damage in marine and offshore environments are major causes of primary steel strength degradation in OWS. Corrosion can reduce the thickness of structural components which may lead towards fatigue crack initiation and buckling. These failure mechanisms affect tower service life and may result in catastrophic structural failure. Additionally, environmental pollution stemming from corrosion’s by-products is possible. As a result, large financial investments are made yearly for both the prevention and recovery of these drawbacks. The corrosion rate of an OWS is dependent on different characteristics of attack which are influenced by access to oxygen and humidity. Structural degradation can occur due to chemical attack, abrasive action of waves, and microorganism attacks. Inspired by technological and scientific advances in recent years, the purpose of this paper is to discuss the current protective coating system technologies used to protect OWS as well as future perspectives.
      PubDate: 2017-02-11
      DOI: 10.3390/coatings7020025
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 26: Surface Enhanced Raman Scattering Substrates
           Made by Oblique Angle Deposition: Methods and Applications

    • Authors: Hin Chu, Shigeng Song, Cheng Li, Des Gibson
      First page: 26
      Abstract: Surface Enhanced Raman Spectroscopy presents a rapid, non-destructive method to identify chemical and biological samples with up to single molecule sensitivity. Since its discovery in 1974, the technique has become an intense field of interdisciplinary research, typically generating >2000 publications per year since 2011. The technique relies on the localised surface plasmon resonance phenomenon, where incident light can couple with plasmons at the interface that result in the generation of an intense electric field. This field can propagate from the surface from the metal-dielectric interface, so molecules within proximity will experience more intense Raman scattering. Localised surface plasmon resonance wavelength is determined by a number of factors, such as size, geometry and material. Due to the requirements of the surface optical response, Ag and Au are typical metals used for surface enhanced Raman applications. These metals then need to have nano features that improve the localised surface plasmon resonance, several variants of these substrates exist; surfaces can range from nanoparticles in a suspension, electrochemically roughened electrodes to metal nanostructures on a substrate. The latter will be the focus of this review, particularly reviewing substrates made by oblique angle deposition. Oblique angle deposition is the technique of growing thin films so that the material flux is not normal to the surface. Films grown in this fashion will possess nanostructures, due to the atomic self-shadowing effect, that are dependent mainly on the deposition angle. Recent developments, applications and highlights of surface enhanced Raman scattering substrates made by oblique angle deposition will be reviewed.
      PubDate: 2017-02-15
      DOI: 10.3390/coatings7020026
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 27: Coating Qualities Deposited Using Three
           Different Thermal Spray Technologies in Relation with Temperatures and
           Velocities of Spray Droplets

    • Authors: Yasuyuki Kawaguchi, Fumihiro Miyazaki, Masafumi Yamasaki, Yukihiko Yamagata, Nozomi Kobayashi, Katsunori Muraoka
      First page: 27
      Abstract: Three guns based on different thermal spray technologies—namely, gas flame spray, wire arc spray, and wire plasma spray—were operated at each best cost–performance condition, and the resulting spray droplets and deposited coating qualities were investigated. For the former, a simple optical monitoring system was used to measure temperatures and velocities of spray droplets ejected from the guns. On the other hand, for the latter, qualities of coating layers on substrates—namely, surface roughness, atomic composition, hardness, adhesive strength, and porosity—were characterized. Then, these coating qualities were discussed with respect to the measured temperatures and velocities of spray droplets, which revealed novel features in the coatings that have not been seen before, such as atomic composition and hardness strongly dependent on temperature and environments of droplets towards the substrates, and porosity on velocity of droplets impinging onto the substrates.
      PubDate: 2017-02-16
      DOI: 10.3390/coatings7020027
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 28: Improving the Wear Resistance of Moulds for
           the Injection of Glass Fibre–Reinforced Plastics Using PVD Coatings: A
           Comparative Study

    • Authors: Francisco Silva, Rui Martinho, Maria Andrade, António Baptista, Ricardo Alexandre
      First page: 28
      Abstract: It is well known that injection of glass fibre–reinforced plastics (GFRP) causes abrasive wear in moulds’ cavities and runners. Physical vapour deposition (PVD) coatings are intensively used to improve the wear resistance of different tools, also being one of the most promising ways to increase the moulds’ lifespan, mainly when used with plastics strongly reinforced with glass fibres. This work compares four different thin, hard coatings obtained using the PVD magnetron sputtering process: TiAlN, TiAlSiN, CrN/TiAlCrSiN and CrN/CrCN/DLC. The first two are monolayer coatings while the last ones are nanostructured and consist of multilayer systems. In order to carry out the corresponding tribological characterization, two different approaches were selected: A laboratorial method, using micro-abrasion wear tests based on a ball-cratering configuration, and an industrial mode, analysing the wear resistance of the coated samples when inserted in a plastic injection mould. As expected, the wear phenomena are not equivalent and the results between micro-abrasion and industrial tests are not similar due to the different means used to promote the abrasion. The best wear resistance performance in the laboratorial wear tests was attained by the TiAlN monolayer coating while the best performance in the industrial wear tests was obtained by the CrN/TiAlCrSiN nanostructured multilayer coating.
      PubDate: 2017-02-16
      DOI: 10.3390/coatings7020028
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 29: Assessment on the Effects of ZnO and Coated
           

    • Authors: Antonella Marra, Gennaro Rollo, Sossio Cimmino, Clara Silvestre
      First page: 29
      Abstract: This paper compares the properties of iPP based composites and PLA based biocomposites using 5% of ZnO particles or ZnO particles coated with stearic acid as filler. In particular, the effect of coating on the UV stability, thermostability, mechanical, barrier, and antibacterial properties of the polymer matrix were compared and related to the dispersion and distribution of the loads in the polymer matrix and the strength of the adhesion between the matrix and the particles. This survey demonstrated that, among the reported systems, iPP/5%ZnOc and PLA/5%ZnO films are the most suitable active materials for potential application in the active food packaging field.
      PubDate: 2017-02-17
      DOI: 10.3390/coatings7020029
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 30: Effects of Rare Earth Elements on Properties
           of Ni-Base Superalloy Powders and Coatings

    • Authors: Chunlian Hu, Shanglin Hou
      First page: 30
      Abstract: NiCrMoY alloy powders were prepared using inert gas atomization by incorporation of rare earth elements, such as Mo, Nb, and Y into Ni60A powders, the coatings were sprayed by oxy-acetylene flame spray and then remelted with high-frequency induction. The morphologies, hollow particle ratio, particle-size distribution, apparent density, flowability, and the oxygen content of the NiCrMoY alloy powders were investigated, and the microstructure and hardness of the coatings were evaluated by optical microscopy (OM). Due to incorporation of the rare earth elements of Mo, Nb, or Y, the majority of the NiCrMoY alloy particles are near-spherical, the minority of which have small satellites, the surface of the particles is smoother and hollow particles are fewer, the particles exhibit larger apparent density and lower flowability than those of particles without incorporation, i.e., Ni60A powders, and particle-size distribution exhibits a single peak and fits normal distribution. The microstructure of the NiCrMoY alloy coatings exhibits finer structure and Rockwell hardness HRC of 60–63 in which the bulk- and needle-like hard phases are formed.
      PubDate: 2017-02-16
      DOI: 10.3390/coatings7020030
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 31: Microstructural Changes of Al Hot-Dipped P91
           Steel during High-Temperature Oxidation

    • Authors: Muhammad Abro, Dong Lee
      First page: 31
      Abstract: The 9Cr-1Mo steel (ASTM P91) was hot-dip aluminized, and its microstructural changes during oxidation were studied. Before oxidation, the coating consisted of (Al-rich topcoat containing a small amount of Al5Fe2 and Al13Fe4)/(Al13Fe4-rich, Al13Fe4-containing alloy layer)/(Al5Fe2 alloy layer containing a small amount of Al9Cr4 precipitates), from the surface. During oxidation at 700–900 °C for 20–100 h, Al diffused inward and the substrate elements migrated outward to broaden and soften the coating, and also to transform (high Al)-Fe intermetallics to (low Al)-Fe intermetallics. The phases in the coating progressively transformed during oxidation as follows; (Al-rich topcoat)/(Al5Fe2–rich, Al13Fe4-containing alloy layer)/(Al5Fe2 alloy layer)→(α-Al2O3 scale)/(Al13Fe4–rich, Al5Fe2-containing layer)/(Al5Fe2 layer)/(AlFe interlayer)→(α-Al2O3 scale)/(AlFe–rich, Al5Fe2-containing layer)/(AlFe layer)/(AlFe3 layer))→((α-Al2O3, Fe2O3)-mixed scale)/(AlFe3 layer)/(Fe(Al) layer) from the surface. As the oxidation progressed, the scale changed from α-Al2O3 to the (α-Al2O3, Fe2O3)-mixture, which provided the necessary oxidation resistance.
      PubDate: 2017-02-17
      DOI: 10.3390/coatings7020031
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 32: Damping Optimization of Hard-Coating Thin
           Plate by the Modified Modal Strain Energy Method

    • Authors: Wei Sun, Rong Liu
      First page: 32
      Abstract: Due to the medium and small damping characteristics of the hard coating compared with viscoelastic materials, the classical modal strain energy (CMSE) method cannot be applied to the prediction of damping characteristics of hard-coating composite structure directly. In this study, the CMSE method was modified in order to be suitable for this calculation, and then the damping optimization of the hard-coating thin plate was carried out. First, the solution formula of modified modal strain energy (MMSE) method was derived and the relevant calculation procedure was proposed. Then, based on the principle that depositing the hard coating on the locations where modal strain energy is higher, the damping optimization method and procedure were presented. Next, a cantilever thin plate coated with Mg-Al hard coating was taken as an example to demonstrate the solution of the modal damping parameters for the composite plate. Finally, the optimization of coating location was studied according to the proposed method for the cantilever thin plate, and the effect of the coating area on the damping characteristics of hard-coating plate was also discussed.
      PubDate: 2017-02-17
      DOI: 10.3390/coatings7020032
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 33: Static and Dynamic Magnetization Investigation
           in Permalloy Electrodeposited onto High Resistive N-Type Silicon
           Substrates

    • Authors: Kenedy Freitas, José Toledo, Leandro Figueiredo, Paulo Morais, Jorlandio Felix, Clodoaldo de Araujo
      First page: 33
      Abstract: The present study reports on the development of permalloy thin films obtained by electrodeposition onto low-doped n-type silicon substrates. While changing from non-percolated clusters into percolated thin films upon increasing the electrodeposition time, the static and dynamic magnetic properties of the as-obtained structures were investigated. We found the experimental magnetic results to be in very good agreement with the simulations performed by solving the Landau-Lifshitz for the dynamics of the magnetic moment. For short electrodeposition times we found the static and dynamic magnetization behavior of the as-formed nanoclusters evidencing vortex magnetization with random chirality and polarization, which is explained in terms of dipolar interaction minimization. Indeed, it is herein emphasized that recent applications of ferromagnetic materials in silicon-based spintronic devices, such as logic and bipolar magnetic transistors and magnetic memories, have revived the possible utilization of low cost and simple electrodeposition techniques for the development of these upcoming hetero-nanostructured devices.
      PubDate: 2017-02-20
      DOI: 10.3390/coatings7020033
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 34: SnS Thin Film Solar Cells: Perspectives and
           Limitations

    • Authors: Simone Di Mare, Daniele Menossi, Andrei Salavei, Elisa Artegiani, Fabio Piccinelli, Arun Kumar, Gino Mariotto, Alessandro Romeo
      First page: 34
      Abstract: Thin film solar cells have reached commercial maturity and extraordinarily high efficiency that make them competitive even with the cheaper Chinese crystalline silicon modules. However, some issues (connected with presence of toxic and/or rare elements) are still limiting their market diffusion. For this reason new thin film materials, such as Cu2ZnSnS4 or SnS, have been introduced so that expensive In and Te, and toxic elements Se and Cd, are substituted, respectively, in CuInGaSe2 and CdTe. To overcome the abundance limitation of Te and In, in recent times new thin film materials, such as Cu2ZnSnS4 or SnS, have been investigated. In this paper we analyze the limitations of SnS deposition in terms of reproducibility and reliability. SnS deposited by thermal evaporation is analyzed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy. The raw material is also analyzed and a different composition is observed according to the different number of evaporation (runs). The sulfur loss represents one of the major challenges of SnS solar cell technology.
      PubDate: 2017-02-22
      DOI: 10.3390/coatings7020034
      Issue No: Vol. 7, No. 2 (2017)
       
  • Coatings, Vol. 7, Pages 5: Shape Memory and Huge Superelasticity in
           Ni–Mn–Ga Glass-Coated Fibers

    • Authors: Lei Shao, Yangyong Zhao, Alejandro Jiménez, Manuel Vázquez, Yong Zhang
      First page: 5
      Abstract: Ni–Mn–Ga polycrystalline alloy fibers with diameters of 33 μm are reported to exhibit significantly improved ductility and huge superelastic and shape memory strains in comparison to conventional brittle bulk polycrystalline alloys. Particularly, the recoverable strain of the Ni54.9–Mn23.5–Ga21.6 fiber can be as high as 10% at 40 °C. Such optimized behavior has been achieved by a suitable fabrication process via a glass-coating melt spinning method. The superelastic properties at different temperatures and the shape memory effect of Ni54.9–Mn23.5–Ga21.6 fibers were investigated.
      PubDate: 2017-01-03
      DOI: 10.3390/coatings7010005
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 6: Acknowledgement to Reviewers of Coatings in
           2016

    • Authors: Coatings Editorial Office
      First page: 6
      Abstract: The editors of Coatings would like to express their sincere gratitude to the following reviewers  for assessing manuscripts in 2016.[...]
      PubDate: 2017-01-10
      DOI: 10.3390/coatings7010006
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 7: Effects of Different Levels of Boron on
           Microstructure and Hardness of CoCrFeNiAlxCu0.7Si0.1By High-Entropy Alloy
           Coatings by Laser Cladding

    • Authors: Yizhu He, Jialiang Zhang, Hui Zhang, Guangsheng Song
      First page: 7
      Abstract: High-entropy alloys (HEAs) are novel solid solution strengthening metallic materials, some of which show attractive mechanical properties. This paper aims to reveal the effect of adding small atomic boron on the interstitial solid solution strengthening ability in the laser cladded CoCrFeNiAlxCu0.7Si0.1By (x = 0.3, x = 2.3, and 0.3 ≤ y ≤ 0.6) HEA coatings. The results show that laser rapid solidification effectively prevents brittle boride precipitation in the designed coatings. The main phase is a simple face-centered cubic (FCC) matrix when the Al content is equal to 0.3. On the other hand, the matrix transforms to single bcc solid solution when x increases to 2.3. Increasing boron content improves the microhardness of the coatings, but leads to a high degree of segregation of Cr and Fe in the interdendritic microstructure. Furthermore, it is worth noting that CoCrFeNiAl0.3Cu0.7Si0.1B0.6 coatings with an FCC matrix and a modulated structure on the nanometer scale exhibit an ultrahigh hardness of 502 HV0.5.
      PubDate: 2017-01-11
      DOI: 10.3390/coatings7010007
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 8: Assessment of Environmental Performance of TiO2
           Nanoparticles Coated Self-Cleaning Float Glass

    • Authors: Martina Pini, Erika Cedillo González, Paolo Neri, Cristina Siligardi, Anna Ferrari
      First page: 8
      Abstract: In recent years, superhydrophilic and photocatalytic self-cleaning nanocoatings have been widely used in the easy-to-clean surfaces field. In the building sector, self-cleaning glass was one of the first nanocoating applications. These products are based on the photocatalytic property of a thin layer of titanium dioxide (TiO2) nanoparticles deposited on the surface of any kind of common glass. When exposed to UV radiation, TiO2 nanoparticles react with the oxygen and water molecules adsorbed on their surface to produce radicals leading to oxidative species. These species are able to reduce or even eliminate airborne pollutants and organic substances deposited on the material’s surface. To date, TiO2 nanoparticles’ benefits have been substantiated; however, their ecological and human health risks are still under analysis. The present work studies the ecodesign of the industrial scale-up of TiO2 nanoparticles self-cleaning coated float glass production performed by the life cycle assessment (LCA) methodology and applies new human toxicity indicators to the impact assessment stage. Production, particularly the TiO2 nanoparticle application, is the life cycle phase most contributing to the total damage. According to the ecodesign approach, the production choices carried out have exacerbated environmental burdens.
      PubDate: 2017-01-12
      DOI: 10.3390/coatings7010008
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 9: Thickness Measurement Methods for Physical
           Vapor Deposited Aluminum Coatings in Packaging Applications: A Review

    • Authors: Martina Lindner, Markus Schmid
      First page: 9
      Abstract: The production of barrier packaging materials, e.g., for food, by physical vapor deposition (PVD) of inorganic coatings such as aluminum on polymer substrates is an established and well understood functionalization technique today. In order to achieve a sufficient barrier against gases, a coating thickness of approximately 40 nm aluminum is necessary. This review provides a holistic overview of relevant methods commonly used in the packaging industry as well as in packaging research for determining the aluminum coating thickness. The theoretical background, explanation of methods, analysis and effects on measured values, limitations, and resolutions are provided. In industrial applications, quartz micro balances (QCM) and optical density (OD) are commonly used for monitoring thickness homogeneity. Additionally, AFM (atomic force microscopy), electrical conductivity, eddy current measurement, interference, and mass spectrometry (ICP-MS) are presented as more packaging research related methods. This work aims to be used as a guiding handbook regarding the thickness measurement of aluminum coatings for packaging technologists working in the field of metallization.
      PubDate: 2017-01-14
      DOI: 10.3390/coatings7010009
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 10: Photocatalytic Properties of Doped TiO2
           Coatings Deposited Using Reactive Magnetron Sputtering

    • Authors: Parnia Navabpour, Kevin Cooke, Hailin Sun
      First page: 10
      Abstract: Mechanically robust photocatalytic titanium oxide coatings can be deposited using reactive magnetron sputtering. In this article, we investigate the effect of doping on the activity of reactively sputtered TiO2. Silver, copper and stainless steel targets were used to co-deposit the dopants. The films were characterised using XRD, SEM and EDX. Adhesion and mechanical properties were evaluated using scratch testing and nano-indentation, respectively, and confirmed that the coatings had excellent adhesion to the stainless steel substrate. All coatings showed superhydrophilicity under UV irradiation. A methylene blue degradation test was used to assess their photocatalytic activity and showed all coatings to be photoactive to varying degrees, dependent upon the dopant, its concentration and the resulting coating structure. The results demonstrated that copper doping at low concentrations resulted in the coatings with the highest photocatalytic activity under both UV and fluorescent light irradiation.
      PubDate: 2017-01-17
      DOI: 10.3390/coatings7010010
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 11: Regenerable Antibacterial Cotton Fabric by
           Plasma Treatment with Dimethylhydantoin: Antibacterial Activity against S.
           aureus

    • Authors: Chang-E. Zhou, Chi-wai Kan, Jukka Matinlinna, James Tsoi
      First page: 11
      Abstract: This study examined the influence of variables in a finishing process for making cotton fabric with regenerable antibacterial properties against Staphylococcus aureus (S. aureus). 5,5-dimethylhydantoin (DMH) was coated onto cotton fabric by a pad-dry-plasma-cure method. Sodium hypochlorite was used for chlorinating the DMH coated fabric in order to introduce antibacterial properties. An orthogonal array testing strategy (OATS) was used in the finishing process for finding the optimum treatment conditions. After finishing, UV-Visible spectroscopy, Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) were employed to characterise the properties of the treated cotton fabric, including the concentration of chlorine, morphological properties, and functional groups. The results show that cotton fabric coated with DMH followed by plasma treatment and chlorination can inhibit S. aureus and that the antibacterial property is regenerable.
      PubDate: 2017-01-18
      DOI: 10.3390/coatings7010011
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 12: On the Durability and Wear Resistance of
           Transparent Superhydrophobic Coatings

    • Authors: Ilker Bayer
      First page: 12
      Abstract: Transparent liquid repellent coatings with exceptional wear and abrasion resistance are very demanding to fabricate. The most important reason for this is the fact that majority of the transparent liquid repellent coatings have so far been fabricated by nanoparticle assembly on surfaces in the form of films. These films or coatings demonstrate relatively poor substrate adhesion and rubbing induced wear resistance compared to polymer-based transparent hydrophobic coatings. However, recent advances reported in the literature indicate that considerable progress has now been made towards formulating and applying transparent, hydrophobic and even oleophobic coatings onto various substrates which can withstand certain degree of mechanical abrasion. This is considered to be very promising for anti-graffiti coatings or treatments since they require resistance to wear abrasion. Therefore, this review intends to highlight the state-of-the-art on materials and techniques that are used to fabricate wear resistant liquid repellent transparent coatings so that researchers can assess various aptitudes and limitations related to translating some of these technologies to large scale stain repellent outdoor applications.
      PubDate: 2017-01-18
      DOI: 10.3390/coatings7010012
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 13: Numerical and Experimental Investigation on
           the Spray Coating Process Using a Pneumatic Atomizer: Influences of
           Operating Conditions and Target Geometries

    • Authors: Qiaoyan Ye, Karlheinz Pulli
      First page: 13
      Abstract: This paper presents a numerical simulation of the spray painting process using a pneumatic atomizer with the help of a computational fluid dynamics code. The droplet characteristics that are necessary for the droplet trajectory calculation were experimentally investigated using different shaping air flow rates. It was found that the droplet size distribution depends on both the atomizing and the shaping air flow rate. An injection model for creating the initial droplet conditions is necessary for the spray painting simulation. An approach for creating these initial conditions has been proposed, which takes different operating conditions into account and is suitable for practical applications of spray coating simulation using spray guns. Further, tests on complicated targets and complex alignments of the atomizer have been carried out to verify this numerical approach. The results confirm the applicability and reliability of the chosen method for the painting process.
      PubDate: 2017-01-18
      DOI: 10.3390/coatings7010013
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 14: Combustion Synthesis during Flame Spraying
           (“CAFSY”) for the Production of Catalysts on Substrates

    • Authors: Galina Xanthopoulou, Amalia Marinou, Konstantinos Karanasios, George Vekinis
      First page: 14
      Abstract: Combustion-assisted flame spraying (“CAFSY”) has been used to produce catalytically active nickel aluminide coatings on ceramic substrates. Their catalytic activity was studied in CO2 (dry) reforming of methane, which is particularly significant for environmental protection as well as production of synthesis gas (CO + H2). By varying the CAFSY processing parameters, it is possible to obtain a range of Ni–Al alloys with various ratios of catalytically active phases on the substrate. The influence of the number of coating layers and the type of substrate on the final catalyst composition and on the catalytic activity of the CAFSY coatings was studied and is presented here. The morphology and microstructure of the composite coatings were determined by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) elemental analysis, X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) specific area analysis. Catalytic tests for dry reforming of methane were carried out using crushed pellets from the coatings at temperatures of 750–900 °C, and gas chromatography showed that methane conversion approached 88% whereas that of carbon dioxide reached 100%. The H2/CO ratio in the synthesis gas produced by the reaction varied from about 0.7 to over 1.2, depending on the catalyst and substrate type and testing temperature.
      PubDate: 2017-01-20
      DOI: 10.3390/coatings7010014
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 15: MHD Flow and Heat Transfer Analysis in the
           Wire Coating Process Using Elastic-Viscous

    • Authors: Zeeshan Khan, Rehan Shah, Saeed Islam, Hamid Jan, Bilal Jan, Haroon-Ur Rasheed, Aurangzeeb Khan
      First page: 15
      Abstract: The most important plastic resins used for wire coating are polyvinyl chloride (PVC), nylon, polysulfone, and low-/high-density polyethylene (LDPE/HDPE). In this article, the coating process is performed using elastic-viscous fluid as a coating material for wire coating in a pressure type coating die. The elastic-viscous fluid is electrically conducted in the presence of an applied magnetic field. The governing non-linear equations are modeled and then solved analytically by utilizing an Adomian decomposition method (ADM). The convergence of the series solution is established. The results are also verified by Optimal Homotopy Asymptotic Method (OHAM). The effect of different emerging parameters such as non-Newtonian parameters α and β, magnetic parameter Mand the Brinkman number Br on solutions (velocity and temperature profiles) are discussed through several graphs. Additionally, the current results are compared with published work already available.
      PubDate: 2017-01-22
      DOI: 10.3390/coatings7010015
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 16: Investigation of the Corrosion Behavior of
           Electroless Ni-P Coating in Flue Gas Condensate

    • Authors: Hejie Yang, Yimin Gao, Weichao Qin
      First page: 16
      Abstract: The corrosion behavior of Ni-P coating deposited on 3003 aluminum alloy in flue gas condensate was investigated by electrochemical approaches. The results indicated that nitrite acted as a corrosion inhibitor. The inhibiting effect of nitrite was reduced in solutions containing sulfate or nitrate. Chloride and sulfate accelerated the corrosion of Ni-P coatings greatly. This can provide important information for the researchers to develop special Ni-P coatings with high corrosion resistance in the flue gas condensate.
      PubDate: 2017-01-19
      DOI: 10.3390/coatings7010016
      Issue No: Vol. 7, No. 1 (2017)
       
  • Coatings, Vol. 7, Pages 1: Weathering of Two Anti-Graffiti Protective
           Coatings on Concrete Paving Slabs

    • Authors: Paula Carmona-Quiroga, Robert Jacobs, Heather Viles
      First page: 1
      Abstract: The durability of anti-graffiti coatings is of special relevance since, unlike other protective treatments, they are not only affected by environmental factors, but also by often aggressive cleaning procedures. However, little is known about the long-term performance of either permanent or sacrificial coatings. This study explores the durability of two commercial coatings on concrete paving slabs under both natural and artificial ageing tests. The results of this research show that a fluorinated polyurethane and a crystalline micro wax weathered in less than 2000 h in a chamber with UVB radiation and after one year of outdoor exposure in the south of England. The former weathered by getting yellow and dark, and eventually, only under the accelerated ageing test, by losing its adhesion to the concrete slabs, and the latter weathered by getting dark, cracked and by reducing its water repellency under natural conditions. Cleaning efficiency of the protected surfaces from graffiti paints was therefore diminished, particularly when pressurized water spray was used on the polyurethane coated surfaces, since the treatment was partially removed and the concrete surface eroded.
      PubDate: 2016-12-22
      DOI: 10.3390/coatings7010001
      Issue No: Vol. 7, No. 1 (2016)
       
  • Coatings, Vol. 7, Pages 2: Study on the Growth of Holes in Cold Spraying
           via Numerical Simulation and Experimental Methods

    • Authors: Guosheng Huang, Hongren Wang, Xiangbo Li, Lukuo Xing
      First page: 2
      Abstract: Cold spraying is a promising method for rapid prototyping due to its high deposition efficiency and high-quality bonding characteristic. However, many researchers have noticed that holes cannot be replenished and will grow larger and larger once formed, which will significantly decrease the deposition efficiency. No work has yet been done on this problem. In this paper, a computational simulation method was used to investigate the origins of these holes and the reasons for their growth. A thick copper coating was deposited around the pre-drilled, micro-size holes using a cold spraying method on copper substrate to verify the simulation results. The results indicate that the deposition efficiency inside the hole decreases as the hole become deeper and narrower. The repellant force between the particles perpendicular to the impaction direction will lead to porosity if the particles are too close. There is a much lower flattening ratio for successive particles if they are too close at the same location, because the momentum energy contributes to the former particle’s deformation. There is a high probability that the above two phenomena, resulting from high powder-feeding rate, will form the original hole, which will grow larger and larger once it is formed. It is very important to control the powder feeding rate, but the upper limit is yet to be determined by further simulation and experimental investigation.
      PubDate: 2016-12-30
      DOI: 10.3390/coatings7010002
      Issue No: Vol. 7, No. 1 (2016)
       
  • Coatings, Vol. 7, Pages 3: Study of a Particle Based Films Cure Process by
           High-Frequency Eddy Current Spectroscopy

    • Authors: Iryna Patsora, Henning Heuer, Susanne Hillmann, Dmytro Tatarchuk
      First page: 3
      Abstract: Particle-based films are today an important part of various designs and they are implemented in structures as conductive parts, i.e., conductive paste printing in the manufacture of Li-ion batteries, solar cells or resistive paste printing in IC. Recently, particle based films were also implemented in the 3D printing technique, and are particularly important for use in aircraft, wind power, and the automotive industry when incorporated onto the surface of composite structures for protection against damages caused by a lightning strike. A crucial issue for the lightning protection area is to realize films with high homogeneity of electrical resistance where an in-situ noninvasive method has to be elaborated for quality monitoring to avoid undesirable financial and time costs. In this work the drying process of particle based films was investigated by high-frequency eddy current (HFEC) spectroscopy in order to work out an automated in-situ quality monitoring method with a focus on the electrical resistance of the films. Different types of particle based films deposited on dielectric and carbon fiber reinforced plastic substrates were investigated in the present study and results show that the HFEC method offers a good opportunity to monitor the overall drying process of particle based films. Based on that, an algorithm was developed, allowing prediction of the final electrical resistance of the particle based films throughout the drying process, and was successfully implemented in a prototype system based on the EddyCus® HFEC device platform presented in this work. This prototype is the first solution for a portable system allowing HFEC measurement on huge and uneven surfaces.
      PubDate: 2016-12-28
      DOI: 10.3390/coatings7010003
      Issue No: Vol. 7, No. 1 (2016)
       
  • Coatings, Vol. 7, Pages 4: Influence of Isothermal Heat Treatment on
           Porosity and Crystallite Size in Axial Suspension Plasma Sprayed Thermal
           Barrier Coatings for Gas Turbine Applications

    • Authors: Ashish Ganvir, Nicolaie Markocsan, Shrikant Joshi
      First page: 4
      Abstract: Axial suspension plasma spraying (ASPS) is an advanced thermal spraying technique, which enables the creation of specific microstructures in thermal barrier coatings (TBCs) used for gas turbine applications. However, the widely varying dimensional scale of pores, ranging from a few nanometers to a few tenths of micrometers, makes it difficult to experimentally measure and analyze porosity in SPS coatings and correlate it with thermal conductivity or other functional characteristics of the TBCs. In this work, an image analysis technique carried out at two distinct magnifications, i.e., low (500×) and high (10,000×), was adopted to analyze the wide range of porosity. Isothermal heat treatment of five different coatings was performed at 1150 °C for 200 h under a controlled atmosphere. Significant microstructural changes, such as inter-columnar spacing widening or coalescence of pores (pore coarsening), closure or densification of pores (sintering) and crystallite size growth, were noticed in all the coatings. The noted changes in thermal conductivity of the coatings following isothermal heat treatment are attributable to sintering, crystallite size growth and pore coarsening.
      PubDate: 2016-12-28
      DOI: 10.3390/coatings7010004
      Issue No: Vol. 7, No. 1 (2016)
       
  • Coatings, Vol. 6, Pages 41: Gelatin-Based Films and Coatings for Food
           Packaging Applications

    • Authors: Marina Ramos, Arantzazu Valdés, Ana Beltrán, María Garrigós
      First page: 41
      Abstract: This review discusses the latest advances in the composition of gelatin-based edible films and coatings, including nanoparticle addition, and their properties are reviewed along their potential for application in the food packaging industry. Gelatin is an important biopolymer derived from collagen and is extensively used by various industries because of its technological and functional properties. Nowadays, a very wide range of components are available to be included as additives to improve its properties, as well as its applications and future potential. Antimicrobials, antioxidants and other agents are detailed due to the fact that an increasing awareness among consumers regarding healthy lifestyle has promoted research into novel techniques and additives to prolong the shelf life of food products. Thanks to its ability to improve global food quality, gelatin has been particularly considered in food preservation of meat and fish products, among others.
      PubDate: 2016-09-28
      DOI: 10.3390/coatings6040041
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 42: Molecularly Imprinted Polymer/Metal Organic
           Framework Based Chemical Sensors

    • Authors: Zhenzhong Guo, Anca Florea, Mengjuan Jiang, Yong Mei, Weiying Zhang, Aidong Zhang, Robert Săndulescu, Nicole Jaffrezic-Renault
      First page: 42
      Abstract: The present review describes recent advances in the concept of molecular imprinting using metal organic frameworks (MOF) for development of chemical sensors. Two main strategies regarding the fabrication, performance and applications of recent sensors based on molecularly imprinted polymers associated with MOF are presented: molecularly imprinted MOF films and molecularly imprinted core-shell nanoparticles using MOF as core. The associated transduction modes are also discussed. A brief conclusion and future expectations are described herein.
      PubDate: 2016-10-05
      DOI: 10.3390/coatings6040042
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 43: Translation Effects in Fluorine Doped Tin
           Oxide Thin Film Properties by Atmospheric Pressure Chemical Vapour
           Deposition

    • Authors: Mohammad Afzaal, Heather Yates, John Hodgkinson
      First page: 43
      Abstract: In this work, the impact of translation rates in fluorine doped tin oxide (FTO) thin films using atmospheric pressure chemical vapour deposition (APCVD) were studied. We demonstrated that by adjusting the translation speeds of the susceptor, the growth rates of the FTO films varied and hence many of the film properties were modified. X-ray powder diffraction showed an increased preferred orientation along the (200) plane at higher translation rates, although with no actual change in the particle sizes. A reduction in dopant level resulted in decreased particle sizes and a much greater degree of (200) preferred orientation. For low dopant concentration levels, atomic force microscope (AFM) studies showed a reduction in roughness (and lower optical haze) with increased translation rate and decreased growth rates. Electrical measurements concluded that the resistivity, carrier concentration, and mobility of films were dependent on the level of fluorine dopant, the translation rate and hence the growth rates of the deposited films.
      PubDate: 2016-10-12
      DOI: 10.3390/coatings6040043
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 44: Atmospheric-Pressure Plasma Jet Processed
           Pt-Decorated Reduced Graphene Oxides for Counter-Electrodes of
           Dye-Sensitized Solar Cells

    • Authors: Ting-Hao Wan, Yi-Fan Chiu, Chieh-Wen Chen, Cheng-Che Hsu, I-Chun Cheng, Jian-Zhang Chen
      First page: 44
      Abstract: Ultrafast atmospheric-pressure plasma jet (APPJ) processed Pt-decorated reduced graphene oxides (rGOs) were used as counter-electrodes in dye-sensitized solar cells (DSSCs). Pastes containing rGO, ethyl cellulose, terpineol, and chloroplatinic acid were screen-printed and sintered by nitrogen dc-pulse APPJs. Pt nanodots were uniformly distributed on the rGO flakes. When using Pt-decorated rGOs as the counter electrodes of DSSCs, the efficiency of the DSSC first increased and then decreased as the APPJ processing time increased. Nitrogen APPJs can effectively remove organic binders and can reduce chloroplatinic acid to Pt, thereby improving the efficiency of DSSCs. However, over-calcination by APPJ can damage the graphenes and degrade the DSSCs. The addition of Pt mainly improves the fill factor, which thereby increases the efficiency of DSSCs. The optimized APPJ processing time was merely 9 s owing to the vigorous interaction among the rGOs, chloroplatinic acid and nitrogen APPJs.
      PubDate: 2016-10-13
      DOI: 10.3390/coatings6040044
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 45: Assessing the Protective Quality of Wax
           Coatings on Bronze Sculptures Using Hydrogel Patches in Impedance
           Measurements

    • Authors: Alice England, Kathryn Hosbein, Capri Price, Morgan Wylder, Kenna Miller, Tami Clare
      First page: 45
      Abstract: In this work, we used chemically cross-linked acrylamide-based hydrogel patches that have been specifically developed for use as solid electrolytes in Electrochemical Impedance Spectroscopy to measure the impedance of two waxed bronze sculptures at the Seattle Art Museum’s (SAM) Olympic Sculpture Park (OSP) and compare those results to laboratory test panels. We determined that the impedance response in the frequency range in which measurements may be taken (10 kHz to 1 MHz) is mostly capacitive and that a freshly applied wax coating should ideally be less than 1 nF·cm−2 for optimal protective performance.
      PubDate: 2016-10-13
      DOI: 10.3390/coatings6040045
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 46: Effect of Surface Pretreatment on Quality and
           Electrochemical Corrosion Properties of Manganese Phosphate on S355J2 HSLA
           Steel

    • Authors: Filip Pastorek, Kamil Borko, Stanislava Fintová, Daniel Kajánek, Branislav Hadzima
      First page: 46
      Abstract: High strength low alloy (HSLA) steels exhibit many outstanding properties for industrial applications but suffer from unsatisfactory corrosion resistance in the presence of aggressive chlorides. Phosphate coatings are widely used on the surface of steels to improve their corrosion properties. This paper evaluates the effect of a manganese phosphate coating prepared after various mechanical surface treatments on the electrochemical corrosion characteristics of S355J2 steel in 0.1 M NaCl electrolyte simulating aggressive sea atmosphere. The manganese phosphate coating was created in a solution containing H3PO4, MnO2, dissolved low carbon steel wool, and demineralised H2O. Scanning electron microscopy (SEM) was used for surface morphology observation supported by energy-dispersive X-ray analysis (EDX). The electrochemical corrosion characteristics were assessed by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD) measurements in the solution of 0.1 M NaCl. Method of equivalent circuits and Tafel-extrapolation were used for the analysis of the obtained results. Performed experiments and analysis showed that the morphological and corrosion properties of the surface with manganese phosphate are negatively influenced by sandblasting surface pretreatment.
      PubDate: 2016-10-15
      DOI: 10.3390/coatings6040046
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 47: Low Energy Atomic Photodesorption from Organic
           Coatings

    • Authors: Alessandro Lucchesini, Silvia Gozzini, Carmela Marinelli, Luca Marmugi
      First page: 47
      Abstract: Organic coatings have been widely used in atomic physics during the last 50 years because of their mechanical properties, allowing preservation of atomic spins after collisions. Nevertheless, this did not produce detailed insight into the characteristics of the coatings and their dynamical interaction with atomic vapors. This has changed since the 1990s, when their adsorption and desorption properties triggered a renewed interest in organic coatings. In particular, a novel class of phenomena produced by non-destructive light-induced desorption of atoms embedded in the coating surface was observed and later applied in different fields. Nowadays, low energy non-resonant atomic photodesorption from organic coatings can be considered an almost standard technique whenever large densities of atomic vapors or fast modulation of their concentration are required. In this paper, we review the steps that led to this widespread diffusion, from the preliminary observations to some of the most recent applications in fundamental and applied physics.
      PubDate: 2016-10-17
      DOI: 10.3390/coatings6040047
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 48: Self-Cleaning Mineral Paint for Application in
           Architectural Heritage

    • Authors: Sudipto Pal, Vincenzo Contaldi, Antonio Licciulli, Fabio Marzo
      First page: 48
      Abstract: A mineral silicate paint has been developed for architectural heritage. To enhance durability, any type of organic additive has been avoided. Potassium silicate was the binder agent intended to give strong adherence and durability to stone and concretes. Incorporation of mainly anatase titanium dioxide was intended to act both as a white, bright pigment and as a photocatalyst. Reflectivity analyses on the paint in the visible-to-near infrared wavelength region show high solar heat reflection. The self-cleaning activity of the mineral paint was evaluated by the degradation of organic dyes under solar light irradiation. Anatase titania was effective in decomposing organic and airborne pollutants with the solar radiation. The optical properties and self-cleaning activity were compared with the organic binder-based paints and commercial paints. Developed paints possess high stability: since they contain only inorganic components that do not fade with exposure to solar radiation, photocatalytic self-cleaning capability further enhances such stability.
      PubDate: 2016-10-18
      DOI: 10.3390/coatings6040048
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 49: Atmospheric Plasma Spraying of Single Phase
           Lanthanum Zirconate Thermal Barrier Coatings with Optimized Porosity

    • Authors: Georg Mauer, Linnan Du, Robert Vaßen
      First page: 49
      Abstract: The shortcomings at elevated operation temperatures of the standard material yttria-stabilized zirconia (YSZ) for thermal barrier coatings (TBCs) have initiated many research activities seeking alternatives. One candidate is the pyrochlore lanthanum zirconate La2Zr2O7 (LZ), which is phase-stable to its melting point. At the same time, it shows a lower thermal conductivity and a lower sintering tendency when compared to YSZ. Because of its low thermal expansion coefficient and poor toughness, it is applied in combination with YSZ in double layer TBC systems. It is the current state of knowledge that LZ is prone to lanthanum depletion if processed by plasma spraying. The process conditions have to be selected carefully to avoid this. Furthermore, the amount and morphology of the coating porosity is essential for a good thermo-mechanical performance. In this work, the development and testing of LZ/YSZ double layer TBC systems is described. Initially, suitable basic parameters (torch, plasma gas composition, and power) were tested with respect to coating stoichiometry. Then, microstructures were optimized by adjusting feed rate, spray distance, and by selecting a more appropriate feedstock. Powder particles and coatings were characterized by digital image analysis.
      PubDate: 2016-10-18
      DOI: 10.3390/coatings6040049
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 50: The Effect of Sintering Oxygen Partial
           Pressure on a SmBiO3 Buffer Layer for Coated Conductors via Chemical
           Solution Deposition

    • Authors: Xiaolei Zhu, Yong Zhao, Minghua Pu, Yong Zhang, Hong Zhang, Cuihua Cheng
      First page: 50
      Abstract: The application of high-temperature YBa2Cu3O7−δ (YBCO) superconducting material is a considerable prospect for the growing energy shortages. Here, SmBiO3 (SBO) films were deposited on (100)-orientated yttrium-stabilized zirconia (YSZ) simple crystal substrates via the chemical solution deposition (CSD) approach for coated conductors, and the effects of sintering oxygen partial pressure on SBO films were studied. The crystalline structures and surface morphologies of SBO films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscope (AFM). The optimized growth temperature, the intensity ratios of the SBO (200) peak to the SBO (111) peak, and the crystallinities of SBO films increased with the sintering oxygen partial pressure. The SEM and AFM images displayed a smooth and well-distributed surface in the argon atmosphere. The subsequent YBCO films with superconducting transition temperatures (Tc = 89.5 K, 90.2 K, and 86.2 K) and critical current densities (Jc = 0.88 MA/cm2, 1.69 MA/cm2, and 0.09 MA/cm2; 77 K, self-field) were deposited to further check the qualities of the SBO layer. These results indicated that sintering oxygen partial pressure had an effect on the epitaxial growth of the SBO buffer layer and YBCO superconducting properties. The experimental results may be a usable reference for the epitaxial growth of YBCO-coated conductors and other oxides.
      PubDate: 2016-10-21
      DOI: 10.3390/coatings6040050
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 51: Machining Duplex Stainless Steel: Comparative
           Study Regarding End Mill Coated Tools

    • Authors: Ronny Gouveia, F. Silva, Pedro Reis, A. Baptista
      First page: 51
      Abstract: The difficulties in the machining of duplex stainless steel are well known. However, research on this matter is rather limited. Suppliers offer quite different cutting tools for the same raw material, with end mills of two, three or even four knives and a huge number of distinct coatings, some of them under commercial brands, making it difficult to assess the advantages they offer. Furthermore, there is a remarkable difference among the several types of duplex stainless steel available nowadays on the market. The present work intends to assess the machining performance of different tools, analyzing the behavior and wear mechanisms with two different cutting lengths, keeping constant the machining trajectory. Some other parameters were also kept constant, such as cutting speed, depth of cut and cutting width, as well as feed per tooth. The machining process was carried out under lubricated conditions, using an emulsion of 5% oil in water. Tools provided with a different number of teeth and surface coatings were tested, analyzing the wear behavior of each cutting length using scanning electron microscopy, trying to identify wear performance and how each coating contributes to increased tool life. The surfaces produced were also analyzed by means of profilometry measurements, correlating tool wear and part surface roughness. This comparative study allows determining the advantages of different tools relative to others, based on coatings and tool geometry.
      PubDate: 2016-10-26
      DOI: 10.3390/coatings6040051
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 52: Synthesis of Covalently Cross-Linked
           Colloidosomes from Peroxidized Pickering Emulsions

    • Authors: Nadiya Popadyuk, Andriy Popadyuk, Ihor Tarnavchyk, Olha Budishevska, Ananiy Kohut, Andriy Voronov, Stanislav Voronov
      First page: 52
      Abstract: A new approach to the formation of cross-linked colloidosomes was developed on the basis of Pickering emulsions that were stabilized exclusively by peroxidized colloidal particles. Free radical polymerization and a soft template technique were used to convert droplets of a Pickering emulsion into colloidosomes. The peroxidized latex particles were synthesized in the emulsion polymerization process using amphiphilic polyperoxide copolymers poly(2-tert-butylperoxy-2-methyl-5-hexen-3-ine-co-maleic acid) (PM-1-MAc) or poly[N-(tert-butylperoxymethyl)acrylamide]-co-maleic acid (PM-2-MAc), which were applied as both initiators and surfactants (inisurfs). The polymerization in the presence of the inisurfs results in latexes with a controllable amount of peroxide and carboxyl groups at the particle surface. Peroxidized polystyrene latex particles with a covalently grafted layer of inisurf PM-1-MAc or PM-2-MAc were used as Pickering stabilizers to form Pickering emulsions. A mixture of styrene and/or butyl acrylate with divinylbenzene and hexadecane was applied as a template for the synthesis of colloidosomes. Peroxidized latex particles located at the interface are involved in the radical reactions of colloidosomes formation. As a result, covalently cross-linked colloidosomes were obtained. It was demonstrated that the structure of the synthesized (using peroxidized latex particles) colloidosomes depends on the amount of functional groups and pH during the synthesis. Therefore, the size and morphology of colloidosomes can be controlled by latex particle surface properties.
      PubDate: 2016-10-25
      DOI: 10.3390/coatings6040052
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 53: Fullerene-Based Electron Transport Layers for
           Semi-Transparent MAPbBr3 Perovskite Films in Planar Perovskite Solar Cells
           

    • Authors: Lung-Chien Chen, Zong-Liang Tseng, Jun-Kai Huang, Cheng-Chiang Chen, Sheng Chang
      First page: 53
      Abstract: In this study, four kinds of structures—[6,6]-phenyl-C61-butyric acid methyl ester (PCBM), PCBM/fullerene (C60), C60/bathocuproine (BCP), and PCBM/C60/BCP—were used as electron transport layers, and the structure, and optical and electronic behaviors of MAPbBr3 perovskite layers after annealing treatments were observed. The experimental results indicate that PCBM/C60 bi-layer structure is acceptable for MAPbBr3 planar perovskite solar cells due to electron step transporting. Low-temperature annealing is suitable for smooth and large grain MAPbBr3 films. The semi-transparent yellow C60/PCBM/MAPbBr3/PEDOT:PSS/ITO glass-structure solar cells exhibit the best performance with a power conversion efficiency of 4.19%. The solar cells are revealed to be suitable for application in building integrated photovoltaic (BIPV) systems.
      PubDate: 2016-10-28
      DOI: 10.3390/coatings6040053
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 54: Introduction to Advanced X-ray Diffraction
           Techniques for Polymeric Thin Films

    • Authors: Nicodemus Widjonarko
      First page: 54
      Abstract: X-ray diffraction has been a standard technique for investigating structural properties of materials. However, most common applications in the organic materials community have been restricted to either chemical identification or qualitative strain analysis. Moreover, its use for polymeric thin films has been challenging because of the low structure factor of carbon and the thin film nature of the sample. Here, we provide a short review of advanced X-ray diffraction (XRD) techniques suitable for polymeric thin films, including the type of analysis that can be done and measurement geometries that would compensate low signals due to low carbon structure factor and the thin film nature of the sample. We will also briefly cover the χ -pole figure for texture analysis of ultra-thin film that has recently become commonly used. A brief review of XRD theory is also presented.
      PubDate: 2016-11-01
      DOI: 10.3390/coatings6040054
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 55: Cellular Automata Modelling of Photo-Induced
           Oxidation Processes in Molecularly Doped Polymers

    • Authors: David Goldie
      First page: 55
      Abstract: The possibility of employing cellular automata (CA) to model photo-induced oxidation processes in molecularly doped polymers is explored. It is demonstrated that the oxidation dynamics generated using CA models exhibit stretched-exponential behavior. This dynamical characteristic is in general agreement with an alternative analysis conducted using standard rate equations provided the molecular doping levels are sufficiently low to prohibit the presence of safe-sites which are impenetrable to dissolved oxygen. The CA models therefore offer the advantage of exploring the effect of dopant agglomeration which is difficult to assess from standard rate equation solutions. The influence of UV-induced bleaching or darkening upon the resulting oxidation dynamics may also be easily incorporated into the CA models and these optical effects are investigated for various photo-oxidation product scenarios. Output from the CA models is evaluated for experimental photo-oxidation data obtained from a series of hydrazone-doped polymers.
      PubDate: 2016-11-04
      DOI: 10.3390/coatings6040055
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 56: Emulsion Polymerization of Tung Oil-Based
           Latexes with Asolectin as a Biorenewable Surfactant

    • Authors: Ashley Johns, Kyle Edwards, Sarah Inglesby, Rafael Quirino
      First page: 56
      Abstract: Bio-based vesicles, with potential application in drug delivery and/or catalyst encapsulation, have been prepared by the free radical emulsion co-polymerization of tung oil, divinylbenzene (DVB), n-butyl methacrylate (BMA), and asolectin in a xylene/water mixture. The free radical polymerization was initiated by di-tert-butyl peroxide (DTBP) at 100 °C in a convection oven. Molecular weights of approximately 11,000 Da were measured by Matrix-assisted Laser Desorption/Ionization-Time of Flight (Maldi-TOF) for tung oil-asolectin copolymers, verifying that significant polymerization occurs under the cure conditions employed. The cure of the co-monomer mixture employed in this work was monitored by Dielectric Analysis (DEA), while changes in the Raman spectrum of all co-monomers before and after the cure, along with differential scanning calorimetry (DSC) analysis, have been used to verify the need of a post-cure step and completion of the polymerization reaction. Scanning Transmission Electron Microscopy (STEM) images of the emulsion after polymerization indicate that vesicles were formed, and vesicle size distribution of samples prepared with different amounts of tung oil were determined using a Zetasizer.
      PubDate: 2016-11-04
      DOI: 10.3390/coatings6040056
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 57: Statistical Contact Angle Analyses with the
           High-Precision Drop Shape Analysis (HPDSA) Approach: Basic Principles and
           Applications

    • Authors: Florian Heib, Michael Schmitt
      First page: 57
      Abstract: Surface science, which includes the preparation, development and analysis of surfaces and coatings, is essential in both fundamental and applied as well as in engineering and industrial research. Contact angle measurements using sessile drop techniques are commonly used to characterize coated surfaces or surface modifications. Well-defined surfaces structures at both nanoscopic and microscopic level can be achieved but the reliable characterization by means of contact angle measurements and their interpretation often remains an open question. Thus, we focused our research effort on one main problem of surface science community, which is the determination of correct and valid definitions and measurements of contact angles. In this regard, we developed the high-precision drop shape analysis (HPDSA), which involves a complex transformation of images from sessile drop experiments to Cartesian coordinates and opens up the possibility of a physically meaningful contact angle calculation. To fulfill the dire need for a reproducible contact angle determination/definition, we developed three easily adaptable statistical analyses procedures. In the following, the basic principles of HPDSA will be explained and applications of HPDSA will be illustrated. Thereby, the unique potential of this analysis approach will be illustrated by means of selected examples.
      PubDate: 2016-11-06
      DOI: 10.3390/coatings6040057
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 58: Thermally Sprayed Aluminum Coatings for the
           Protection of Subsea Risers and Pipelines Carrying Hot Fluids

    • Authors: Nataly Ce, Shiladitya Paul
      First page: 58
      Abstract: This paper reports the effect of boiling synthetic seawater on the performance of damaged Thermally Sprayed Aluminum (TSA) on carbon steel. Small defects (4% of the sample’s geometric surface area) were drilled, exposing the steel, and the performance of the coating was analyzed for corrosion potential for different exposure times (2 h, 335 h, and 5000 h). The samples were monitored using linear polarization resistance (LPR) in order to obtain their corrosion rate. Scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used for post-test characterization. The results showed that a protective layer of Mg(OH)2 formed in the damaged area, which protected the underlying steel. Additionally, no coating detachment from the steel near the defect region was observed. The corrosion rate was found to be 0.010–0.015 mm/year after 5000 h in boiling synthetic seawater.
      PubDate: 2016-11-08
      DOI: 10.3390/coatings6040058
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 59: Cylindrical Three-Dimensional Porous Anodic
           Alumina Networks

    • Authors: Pedro Resende, Ruy Sanz, Alejandra Ruiz-de Clavijo, Olga Caballero-Calero, Marisol Martin-Gonzalez
      First page: 59
      Abstract: The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis of the nanostructure revealed the effects of the initial defects on the aluminum surface and the mechanical strains on the integrity of the three-dimensional network. The results evidence the feasibility of obtaining 3D porous anodic alumina on non-planar aluminum substrates.
      PubDate: 2016-11-09
      DOI: 10.3390/coatings6040059
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 60: Performances and Coating Morphology of a
           Siloxane-Based Hydrophobic Product Applied in Different Concentrations on
           a Highly Porous Stone

    • Authors: Mariateresa Lettieri, Maurizio Masieri
      First page: 60
      Abstract: Many polymers, able to confer a hydrophobicity to treated surfaces, have been proposed for the restoration and conservation of civil and monumental buildings. Polysiloxanes, and their precursors, the silanes, have been frequently employed for stone protection. To avoid decay of the treated surfaces, the effectiveness and harmlessness of the treatment need to be carefully evaluated before application in the field. In this study, a commercial alkyl-siloxane was tested as a protective treatment on a highly porous stone, starting from water solutions with different contents of the product. The treatments have been devised to try to balance the requirements and the sustainability of the conservative actions. Sustainability, in terms of costs and environmental impact, is regarded as a key factor in the 21st century. Morphological observations of the stone surface, static contact angle and colour measurements, water vapour transmission test, and tests of water absorption were carried out to characterize the untreated and treated stones. A concentration below the minimum level suggested by the manufacturer was still able to act as a good barrier against water. More concentrated solutions produced polymer accumulation and coatings with extended cracks. The properties of the treated stone were affected by the presence of cracks in the coating.
      PubDate: 2016-11-13
      DOI: 10.3390/coatings6040060
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 61: Development of Mirror Coatings for
           Gravitational Wave Detectors

    • Authors: Stuart Reid, Iain Martin
      First page: 61
      Abstract: The first detections of gravitational waves, GW150914 and GW151226, were associated with the coalescence of stellar mass black holes, heralding the opening of an entirely new way to observe the Universe. Many decades of development were invested to achieve the sensitivities required to observe gravitational waves, with peak strains associated with GW150914 at the level of 10−21. Gravitational wave detectors currently operate as modified Michelson interferometers, where thermal noise associated with the highly reflective mirror coatings sets a critical limit to the sensitivity of current and future instruments. This article presents an overview of the mirror coating development relevant to gravitational wave detection and the prospective for future developments in the field.
      PubDate: 2016-11-16
      DOI: 10.3390/coatings6040061
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 62: Influence of Surface Roughness and Agitation
           on the Morphology of Magnetite Films Electrodeposited on Carbon Steel
           Substrates

    • Authors: Soon-Hyeok Jeon, Won-Ik Choi, Geun-Dong Song, Yeong-Ho Son, Do Hur
      First page: 62
      Abstract: In this work, we investigated the effects of surface roughness and agitation on the morphology of magnetite films electrodeposited from alkaline Fe(III)-triethanolamine (TEA) solutions on carbon steel substrates. The surface roughness of the carbon steel substrates was maintained in the range of 1.64–0.06 μm by using mechanical grinding and polishing methods. The agitation speed was set at 0 and 900 rpm during the electrodeposition process. The particle size and surface roughness value of the magnetite films gradually decreased with decreasing substrate roughness. However, the influence of the substrate roughness on the thickness of the magnetite film was negligible. The morphology of the magnetite film fabricated at 900 rpm appeared to be highly faceted compared to that of the magnetite film produced at 0 rpm. The thickness and surface roughness of the magnetite film significantly increased with the agitation speed, which also significantly affected the electrodeposition efficiency. The effects of substrate surface roughness and agitation on the morphology of magnetite films electrodeposited on carbon steel substrates were also discussed. The obtained results provide critical information for the simulation of magnetite deposits on carbon steel pipes in the secondary systems of nuclear power plants.
      PubDate: 2016-11-16
      DOI: 10.3390/coatings6040062
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 63: Fabrication of Microalloy Nitrided Layer on
           Low Carbon Steel by Nitriding Combined with Surface Nano-Alloying
           Pretreatment

    • Authors: Jian Sun, Quantong Yao
      First page: 63
      Abstract: Surface mechanical attrition treatment (SMAT) is an effective method to accelerate the nitriding process of metallic materials. In this work, a novel technique named surface nano-alloying (SNA) was developed on the basis of surface mechanical attrition treatment, which was employed as a pretreatment for the nitriding of low carbon steel materials. The microstructure and surface properties of treated samples were investigated by SEM, XRD, TEM and the Vickers hardness test. Experimental results showed that a surface alloying layer (Cr element) of about 10–20 μm in thickness was formed on the low carbon steel sample after the surface nano-alloying treatment. After nitriding for the SNA sample, a complex compound layer composed of Fe2–3N, FeCr and Cr2N phases was fabricated. Moreover, the thickness of this compound layer was about 50 μm. Meanwhile, both the surface hardness and wear resistance of the SNA nitrided sample are better that those of the SMAT nitrided sample. This work offers a new approach for improving the nitriding process of steel materials.
      PubDate: 2016-11-17
      DOI: 10.3390/coatings6040063
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 64: Structural Study of Silica Coating Thin Layers
           Prepared from Perhydropolysilazane: Substrate Dependence and Water
           Penetration Structure

    • Authors: Tomotake Niizeki, Sachiko Nagayama, Yoshio Hasegawa, Noboru Miyata, Masae Sahara, Kazuhiro Akutsu
      First page: 64
      Abstract: The structure of perhydropolysilazane (PHPS)-derived silica (PDS) waterproof thin layers synthesized by curing at 60 °C for 1 h and allowed to stand for 48 h at 20 °C on various kinds of substrates was studied. Neutron reflectivity (NR) analysis suggested that uniform PDS thin layers were synthesized on the substrates, and the density of the layers varied depending on the type of substrate. Additionally, since the change in PDS density is correlated with the pKa value of the OH group on the substrate, it can be suggested that the acidity of the substrate would be one of the main factors determining the density of the coated PDS thin layers. For the water penetration structure study, NR analysis revealed that the depth of water penetration into the PDS layers was below 500 Å, and the hydration number of the SiO2 molecule was estimated to be 8.0–9.0. From these results, we concluded that water penetration occurred by the formation of water-pool structures in the PDS layers, and the randomly formed nano-air holes lead to a reduction in the probability of water penetration into the deep regions of the PDS layers.
      PubDate: 2016-11-19
      DOI: 10.3390/coatings6040064
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 65: Corrosion Testing of Thermal Spray Coatings in
           a Biomass Co-Firing Power Plant

    • Authors: Maria Oksa, Jarkko Metsäjoki, Janne Kärki
      First page: 65
      Abstract: Large-scale use of biomass and recycled fuel is increasing in energy production due to climate and energy targets. A 40% cut in greenhouse gas emission compared to 1990 levels and at least a 27% share of renewable energy consumption are set in EU Energy Strategy 2030. Burning fuels with high content of corrosive species such as chlorine and heavy metals causes deterioration of boiler components, shortened lifetime, limited availability of a plant and hence higher maintenance and investment costs and lower thermal and economic efficiency. Coatings can be applied to protect the critical boiler components against high temperature corrosion. In this study, five thermal spray coatings were tested in an actual biomass co-firing boiler for 1300 h with a measurement probe. The coatings were analyzed after the exposure by metallographic means and scanning electron microscope/energy-dispersive X-ray spectroscope (SEM/EDX). The deposits formed on the specimens were analyzed by X-ray fluorescence. At 550 °C, the coatings showed excellent corrosion performance compared to reference material ferritic steel T92. At 750 °C, tube material A263 together with NiCr and NiCrTi had the highest corrosion resistance. To conclude, thermal spray coatings can offer substantial corrosion protection in biomass and recycled fuel burning power plants.
      PubDate: 2016-11-24
      DOI: 10.3390/coatings6040065
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 66: Improving the Performance of Clear Coatings on
           Wood through the Aggregation of Marginal Gains

    • Authors: Philip Evans, Stephan Vollmer, Joseph Kim, George Chan, Sara Kraushaar Gibson
      First page: 66
      Abstract: Remarkable increases in the performance of complex systems can be achieved by a collective approach to optimizing individual factors that influence performance. This approach, termed the aggregation of marginal gains, is tested here as a means of improving the performance of exterior clear-coatings. We focused on five factors that influence clear-coating performance: dimensional stability of wood; photostability of the wood surface; moisture ingress via end-grain; coating flexibility and photostability; and finally coating thickness. We performed preliminary research to select effective wood pre-treatments and durable clear-coatings, and then tested coating systems with good solutions to each of the aforementioned issues (factors). Red oak and radiata pine panels were modified with PF-resin, end-sealed, and thick acrylic, alkyd or spar varnishes were applied to the panels. Panels were exposed to the weather and the level of coating defects was assessed every year over a 4-year period. All of the coatings are performing well on PF-modified pine after 4 years’ outdoor exposure. In contrast, coatings failed after 2 years on unmodified pine and they are failing on PF-modified oak. We conclude that our approach shows promise. Future research will build on the current work by developing solutions to additional factors that influence clear-coating performance.
      PubDate: 2016-11-26
      DOI: 10.3390/coatings6040066
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 67: The Microstructure and Wear Resistance of a
           Copper Matrix Composite Layer on Copper via Nitrogen-Shielded Arc Cladding
           

    • Authors: Yinan Li, Xianbao Liu, Zhikang Zhou, Lei Zhang, Zilong Peng
      First page: 67
      Abstract: A TiN and TiN·Ti2Cu reinforced copper matrix composite layer was cladded onto a T3 copper substrate to improve the anti-wear performance of copper products by means of the nitrogen-shielded gas tungsten arc cladding method (N2-GTAC). Better than the traditional preparation method of TiN, the TiN particles in the cladding layer were in situ generated using N atoms of shielding gas and Ti atoms of pre-deposited metal powders. In addition, the composite phase TiN·Ti2Cu occurred in the cladding layer, which also had a positive effect on anti-wearing. As Ti increased, the amount and grain size of TiN·Ti2Cu and TiN increased as a result. The hardness of the cladding layer increased with the increasing amount of reinforced phase generated in the layer. The hardness of the layer reached a maximum of 410 HV, which is nearly 5.1 times greater than that of copper. The TiN·Ti2Cu- and TiN-reinforced phases improved the wear resistance of the cladding layers. The cladding layer with 15 wt % Ti had the longsest launch stage (600 s) and the lowest fiction coefficient (0.56).
      PubDate: 2016-12-06
      DOI: 10.3390/coatings6040067
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 68: Characterization and Photovoltaic Properties
           of BiFeO3 Thin Films

    • Authors: Yasuhiro Shirahata, Takeo Oku
      First page: 68
      Abstract: Bismuth ferrite (BiFeO3) thin films were prepared by a spin-coating method. Crystal structure and optical properties of the BiFeO3 films were evaluated using X-ray diffraction. The lattice constants, crystallite size, and energy gap of BiFeO3 films depended on the concentration of the BiFeO3 precursor solution. BiFeO3/CH3NH3PbI3 photovoltaic devices were fabricated to investigate photovoltaic properties of BiFeO3. Current density–voltage characteristics of the photovoltaic devices showed rectifying behavior, indicating that BiFeO3 worked as an electron transport layer in CH3NH3PbI3-based photovoltaic devices.
      PubDate: 2016-12-08
      DOI: 10.3390/coatings6040068
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 69: Erratum: Panagopoulos, C.N., et al. Wear
           Behaviour of Nanostructured Polymer-Based Safety Films on Soda-Lime Glass.
           Coatings 2016, 6, 26

    • Authors: C. Panagopoulos, E. Georgiou, G. Tradas, K. Giannakopoulos
      First page: 69
      Abstract: n/a
      PubDate: 2016-12-14
      DOI: 10.3390/coatings6040069
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 70: Durability Analysis and Experimental
           Validation of Environmental Barrier Coating (EBC) Performance Using
           Combined Digital Image Correlation and NDE

    • Authors: Ali Abdul-Aziz, Adam Wroblewski
      First page: 70
      Abstract: To understand the failure mechanism or to predict the spallation life of environmental barrier coatings (EBC) on fiber reinforced ceramic matrix composites, the fracture strength of EBC and the process of the crack growth in EBC layers need to be experimentally determined under standard or simulated engine operating conditions. The current work considers a multi layered barium strontium aluminum silicate (BSAS)-based EBC-coated, melt infiltrated silicon carbide fiber reinforced silicon carbide matrix composite (MI SiC/SiC) specimen that was tensile tested at room temperature. Numerous tests were performed under tensile loading conditions, and the specimen was loaded until failure under pre-determined stress levels. The specimen was examined with optical microscopy, scanning electron microscopy (SEM), computed tomography (CT) scan, and digital image correlation (DIC) camera. Observation from the computed tomography scanning, the SEM, and the optical microscopy did not offer conclusive information concerning the cracks that spawned during the tests. However, inspection with the DIC camera offered some indication that cracks had developed and allowed their detection and the location of their initiation site. Thus, this study provides detailed discussion of the results obtained from the experimental investigation and the nondestructive evaluation (NDE), and it also includes assessment of the stress response predicted by analytical modeling and their impact on EBC durability and crack growth formation under complex loading settings.
      PubDate: 2016-12-16
      DOI: 10.3390/coatings6040070
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 71: Local Electrical Response in Alkaline-Doped
           Electrodeposited CuInSe2/Cu Films

    • Authors: Javier Barón-Miranda, Octavio Calzadilla, Liliana Arvizu-Rodríguez, Jose Fernández-Muñoz, Cesia Guarneros-Aguilar, Fabio Chale-Lara, Ulises Páramo-García, Felipe Caballero-Briones
      First page: 71
      Abstract: The local electrical response in alkaline-doped CuInSe2 films prepared by single-step electrodeposition onto Cu substrates was studied by current-sensing atomic force microscopy. The CuInSe2 (CIS) films were prepared from single baths containing the dopant ions (Li, Na, K or Cs) and were studied by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and photocurrent response. Increased crystallinity and surface texturing as the ion size increased were observed, as well as an enhanced photocurrent response in Cs-doped CIS. Li- and Na-doped films had larger conductivity than the undoped film while the K- and Cs-doped samples displayed shorter currents and the current images indicated strong charge accumulation in the K- and Cs-doped films, forming surface capacitors. Corrected current-sensing AFM IV curves were adjusted with the Shockley equation.
      PubDate: 2016-12-20
      DOI: 10.3390/coatings6040071
      Issue No: Vol. 6, No. 4 (2016)
       
  • Coatings, Vol. 6, Pages 28: Effect of Activated Plastic Films on
           Inactivation of Foodborne Pathogens

    • Authors: Belén Soriano Cuadrado, Pilar Martínez Viedma, Mari López Aguayo, Irene Ortega Blazquez, Maria Grande Burgos, Rubén Pérez Pulido, Antonio Gálvez, Rosario Lucas López
      First page: 28
      Abstract: In the present study, low density polyethylene films were activated by co-extrusion with zinc oxide, zinc acetate or potassium sorbate. Films were also surface-activated with tyrosol singly or in combination with lactic acid or p-hydroxybenzoic acid. Activated films were tested on Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella enterica and Pseudomonas fluorescens. The combinations showing greatest inhibition zones and broadest inhibitory spectrum were the films activated with tyrosol plus p-hydroxybenzoic acid. A small delay in growth of Listeria innocua was observed on seabream packed in ZnO-activated films during refrigerated storage for 7 days. When films activated with 2.5% tyrosol or with 1.5% tyrosol plus 0.5 p-hydroxybenzoic acid were used for vacuum packaging of smoked salmon and smoked tuna challenged with cocktails of S. enterica and L. monocytogenes strains, the combination of tyrosol and p-hydroxybenzoic acid improved inactivation of both pathogens during chill storage compared to films singly activated with tyrosol. The best results were obtained in smoked salmon, since no viable pathogens were detected after 7 days of chill storage for the activated film. Results from the study highlight the potential of plastic films surface-activated with tyrosol and p-hydroxybenzoic acid in the control of foodborne pathogens in smoked seafood.
      PubDate: 2016-07-19
      DOI: 10.3390/coatings6030028
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 29: A Novel Technique for the Deposition of
           Bismuth Tungstate onto Titania Nanoparticulates for Enhancing the Visible
           Light Photocatalytic Activity

    • Authors: Marina Ratova, Peter Kelly, Glen West, Lubomira Tosheva
      First page: 29
      Abstract: A novel powder handling technique was used to allow the deposition of bismuth tungstate coatings onto commercial titanium dioxide photocatalytic nanoparticles. The coatings were deposited by reactive pulsed DC magnetron sputtering in an argon/oxygen atmosphere. The use of an oscillating bowl with rotary particle propagation, positioned beneath two closed-field planar magnetrons, provided uniform coverage of the titania particle surfaces. The bismuth/tungsten atomic ratio of the coatings was controlled by varying the power applied to each target. The resulting materials were characterized by X-ray diffraction, energy-dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (BET) surface area measurements, transmission electron microscopy (TEM), and UV-visible diffuse reflectance spectroscopy. Photocatalytic properties under visible light irradiation were assessed using an acetone degradation test. It was found that deposition of bismuth tungstate onto titania nanoparticles resulted in significant increases in visible light photocatalytic activity, compared to uncoated titania. Of the coatings studied, the highest photocatalytic activity was measured for the sample with a Bi/W atomic ratio of 2/1.
      PubDate: 2016-07-21
      DOI: 10.3390/coatings6030029
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 30: A Surface Photovoltage Study of Surface
           Defects on Co-Doped TiO2 Thin Films Deposited by Spray Pyrolysis

    • Authors: Henry Wafula, Albert Juma, Thomas Sakwa, Robinson Musembi, Justus Simiyu
      First page: 30
      Abstract: Surface photovoltage (SPV) spectroscopy is a powerful tool for studying electronic defects on semiconductor surfaces, at interfaces, and in bulk for a wide range of materials. Undoped and Cobalt-doped TiO2 (CTO) thin films were deposited on Crystalline Silicon (c-Si) and Flourine doped Tin oxide (SnO2:F) substrates by chemical spray pyrolysis at a substrate temperature of 400 °C. The concentration of the Co dopant in the films was determined by Rutherford backscattering spectrometry and ranged between 0 and 4.51 at %. The amplitude of the SPV signals increased proportionately with the amount of Co in the films, which was a result of the enhancement of the slow processes of charge separation and recombination. Photogenerated holes were trapped at the surface, slowing down the time response and relaxation of the samples. The surface states were effectively passivated by a thin In2S3 over-layer sprayed on top of the TiO2 and CTO films.
      PubDate: 2016-07-22
      DOI: 10.3390/coatings6030030
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 31: Non-Cyanide Electrodeposited Ag–PTFE
           Composite Coating Using Direct or Pulsed Current Deposition

    • Authors: Raymond Sieh, Huirong Le
      First page: 31
      Abstract: The effects of FC-4 cationic surfactant on electrodeposited Ag–PTFE composite coating using direct or pulsed currents were studied using scanning electron microscope (SEM), energy dispersive X-ray (EDS), optical microscope, and a linear tribometer. FC-4:PTFE in various ratios were added to a non-cyanide succinimide silver complex bath. Direct or pulsed current method was used at a constant current density to enable comparison between both methods. A high incorporation rate of PTFE was successfully achieved, with pulsed current being highly useful in increasing the amount of PTFE in the composite coating. The study of coating wear under sliding showed that a large majority of the electrodeposited coatings still managed to adhere to the substrate, even after 10 wear cycles of sliding tests. Performance improvements were achieved on all the samples with a coefficient of friction (CoF) between 0.06 and 0.12.
      PubDate: 2016-07-26
      DOI: 10.3390/coatings6030031
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 32: Graphite–Cement Paste: A New Coating of
           Reinforced Concrete Structural Elements for the Application of
           Electrochemical Anti-Corrosion Treatments

    • Authors: Miguel-Ángel Climent, Jesús Carmona, Pedro Garcés
      First page: 32
      Abstract: This paper reviews research carried out towards the development of a novel conductive coating for reinforced concrete structures in order to enable the application of electrochemical anti-corrosion treatments. The coating is composed of a hardened paste containing graphite powder and cement. The applied techniques were electrochemical chloride extraction (ECE), cathodic protection (CP), and cathodic prevention, as well as combined treatments such as ECE-CP. This research has demonstrated their efficiency when using the new conductive coating as an anode system. The influence of the shape of the structural elements on the performance of the electrochemical treatments was also studied. Several characteristics of the coating have been determined, such as conductivity, durability, adhesion to the concrete surfaces, and ease of application. The results demonstrate the adequacy of using this coating as the anode for anti-corrosion treatments on reinforced concrete structural elements of different shapes, for the purpose of extending service life.
      PubDate: 2016-07-28
      DOI: 10.3390/coatings6030032
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 33: Surface-Engineered Fire Protective Coatings
           for Fabrics through Sol-Gel and Layer-by-Layer Methods: An Overview

    • Authors: Giulio Malucelli
      First page: 33
      Abstract: Fabric flammability is a surface-confined phenomenon: in fact, the fabric surface represents the most critical region, through which the mass and heat transfers, responsible for fueling the flame, are controlled and exchanged with the surroundings. More specifically, the heat the fabric surface is exposed to is transferred to the bulk, from which volatile products of thermal degradation diffuse toward the surface and the gas phase, hence feeding the flame. As a consequence, the chemical and physical characteristics of the fabric surface considerably affect the ignition and combustion processes, as the surface influences the flux of combustible volatile products toward the gas phase. In this context, it is possible to significantly modify (and improve) the fire performance of textile materials by “simply” tailoring their surface: currently, one of the most effective approaches exploits the deposition of tailored coatings able to slow down the heat and mass transfer phenomena occurring during the fire stages. This paper reviews the current state of the art related to the design of inorganic, hybrid, or organic flame-retardant coatings suitable for the fire protection of different fabric substrates (particularly referring to cotton, polyester, and their blends). More specifically, the use of sol-gel and layer-by-layer (LbL) methods is thoroughly discussed; then, some recent examples of flame retardant coatings are presented, showing their potential advances and their current limitations.
      PubDate: 2016-07-29
      DOI: 10.3390/coatings6030033
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 34: An Overview on Corrosion-Resistant Coating
           Technologies in Biomass/Waste-to-Energy Plants in Recent Decades

    • Authors: Yuuzou Kawahara
      First page: 34
      Abstract: Highly efficient electric power generation from biomass/waste fuels becomes an important worldwide issue to prevent global warming. In these plants, severe high-temperature corrosion and erosion-corrosion damage occur in boiler tubes influenced by HCl, SOx gases, and chlorides as contaminants in fuels. Coating technologies become important as a countermeasure for such damage, because of the easy maintenance, cost performance, and ease of application on various materials. In severe corrosive conditions of boilers, formation of dense, homogenous, and tough coating layers, as well as protective oxide layers of corrosion-resistant materials, are important. In the last 30 years, materials and coating processes applied in shop and on site have progressed based on many field observations and the consideration of deterioration mechanisms in order to maintain long lifetimes in the plants. Furthermore, new innovative coatings are now being developed by using advanced precise control, nanotechnologies, etc. This paper introduces recent trends of advanced coating developments and applications, such as weld-overlay, cladding, thermal spray coating, and slurry coating for biomass/waste boilers. Furthermore, the evaluation results of deterioration mechanisms and lifetime of coatings, and the future issue for innovative coatings, are presented.
      PubDate: 2016-08-05
      DOI: 10.3390/coatings6030034
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 35: Techniques and Challenges for Characterizing
           Metal Thin Films with Applications in Photonics

    • Authors: Paul Whiteside, Jeffrey Chininis, Heather Hunt
      First page: 35
      Abstract: The proliferation of laser technologies has profoundly increased the demand for high-quality optical thin films whose physical properties are tunable and well defined. Such films are frequently deposited in thicknesses much shorter than the wavelengths of visible light and consequently present challenges for characterization by traditional microscopy. Metal films in particular exemplify these challenges, due to their broad range of refractive indices, optical absorption and often near-complete reflectivity in the visible spectrum. However, due to their relatively consistent crystalline structure, the bulk optical properties of metal thin films are chiefly dependent on their thickness. This review therefore presents a compendium of viable alternative characterization techniques to highlight their respective utilities, limitations and resolutions, specifically with regard to the characterization of the thickness of metal films. Furthermore, this review explicitly addresses the operating theories, methods and analyses relating to the five most predominantly utilized techniques: X-ray Reflectivity (XRR), Spectroscopic Ellipsometry (SE), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). This work is intended as an introductory guide to thin film characterization modalities and their applicability for metal and optically-absorptive films, while also identifying AFM and SEM/EDS as being amongst the more reliable of the techniques.
      PubDate: 2016-08-17
      DOI: 10.3390/coatings6030035
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 36: High Temperature Corrosion Studies of a
           Zirconia Coating: Implications for Waste-to-Energy (WTE) Plants

    • Authors: Dirk Müller, Silke Wöllmer, Donjá Aßbichler, Martin Murer, Soraya Heuss-Aßbichler, Konrad Rieger, Horst Hill, Carsten Härtel, Patrick Masset
      First page: 36
      Abstract: Corrosion of functional parts within waste-to-energy (WTE) plants significantly reduces their efficiency with respect to maintenance costs. Currently, nickel-based alloy claddings, several millimeters thick, are the state of the art as anti-corrosion coating. Another approach is to utilize thermally sprayed multilayer coatings with a zirconia top-coat. Lab-scale experiments under simulated WTE plant conditions and in situ tests within a WTE plant revealed a partially reduced porosity of the zirconia top-coat after the experiments, enabling the coating to act as a barrier against aggressive gases. In a lab-scale experiment sample the pores are filled up with zirconia, while the pores of the in situ samples are filled up with newly formed metal (Cr, Ni, Fe) oxides.
      PubDate: 2016-08-25
      DOI: 10.3390/coatings6030036
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 37: Feasibility of Coloring Bamboo with the
           Application of Natural and Extracted Fungal Pigments

    • Authors: Sarath Vega Gutierrez, Patricia Vega Gutierrez, Auna Godinez, Lauren Pittis, Megan Huber, Savannah Stanton, Sara Robinson
      First page: 37
      Abstract: Fungal pigments, specifically those generated from spalting fungi, are being developed for broader use in the wood and textile industry, and due to their coloration properties, may also be useful as aesthetic bamboo dyes. This paper evaluates the potential use of fungal pigments in bamboo (Phyllostachys spp.), and compares the difference between natural spalting and the direct application of extracted fungal pigments of three known spalting fungi: Scytalidium cuboideum, Scytalidium ganodermophthorum, and Chlorociboria aeruginosa. Bamboo was significantly spalted by S. cuboideum under live inoculation, while the other two fungi did not colonize. For the direct application of fungal pigments, bamboo did not develop internal pigmentation with any pigment, but did develop visible surface color for S. cuboideium and C. aeruginosa. Light microscopy and scanning electron microscopy confirmed the presence of hyphae in bamboo vessels and parenchyma. An HPLC analysis for simple sugars showed the presence of glucose but no sucrose. Results indicate that the extracted pigments of the aforementioned fungi are ideal for the surface treatment of bamboo, while only direct inoculation of S. cuboideum is appropriate for internal coloration.
      PubDate: 2016-08-30
      DOI: 10.3390/coatings6030037
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 38: Coatings Best Paper Award 2016

    • Authors: Alessandro Lavacchi
      First page: 38
      Abstract: Coatings has established the Best Paper Award to recognize its best published articles each year.[...]
      PubDate: 2016-09-02
      DOI: 10.3390/coatings6030038
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 39: Deposition and Characterization of Si-Doped
           Diamond Films Using Tetraethoxysilane onto a WC-Co Substrate

    • Authors: Jianguo Zhang, Xia Ji, Jinsong Bao, Xiaohu Zheng
      First page: 39
      Abstract: Silicon-doped (Si-doped) diamond films were deposited on a Co-cemented tungsten carbide (WC-Co) substrate using the hot filament chemical vapor deposition (HFCVD) method with a mixture of acetone, tetraethoxysilane (TEOS), and hydrogen as the recant source. The as-deposited doped diamond films were characterized with field emission scanning electron microscopy (FE-SEM), Raman spectrum, and X-ray diffraction (XRD). Furthermore, Rockwell C indentation tests were conducted to evaluate the adhesion of the Si-doped diamond films grown on the WC-Co substrate. The results demonstrated that the silicon concentration in the reactant source played an important role in the surface morphology and adhesion of diamond films. The size of diamond grain varied from 3 μm to 500 nm with silicon concentration increasing from 0 to 1.41 atom %. When the silicon concentration rose to 1.81 atom %, the grain size became bigger than that of the lower concentration. The ratio of diamond peak {220}/{111} varied with different silicon concentrations. Raman study features revealed high purity of as-deposited diamond films. The Raman spectra also demonstrated the presence of silicon in the diamond films with Si–Si, Si–C and Si–O bonds. Si-doped diamond films with strong adhesive strength on the WC-Co substrate was beneficial for diamond films applied on cutting tools and wear resistance components.
      PubDate: 2016-09-05
      DOI: 10.3390/coatings6030039
      Issue No: Vol. 6, No. 3 (2016)
       
  • Coatings, Vol. 6, Pages 40: Development of Novel ECTFE Coated PP Composite
           Hollow-Fiber Membranes

    • Authors: Sergio Santoro, Enrico Drioli, Alberto Figoli
      First page: 40
      Abstract: In this work composite hollow-fibers were prepared by dip-coating of commercial polypropylene (PP) with a thin layer of ethylene–chlorotrifluoroethylene copolymer (ECTFE). The employment of N-methyl pyrrolidone (NMP) as solvent improved the polymer processability favoring dip-coating at lower temperature (135 °C). Scanning electron microscopy (SEM) analyses showed that after dip-coating the PP support maintained its microstructure, whereas a thin coated layer of ECTFE on the external surface of the PP hollow-fiber was clearly distinguishable. Membrane characterization evidenced the effects of the concentration of ECTFE in the dope-solution and the time of dip-coating on the thickness of ECTFE layer and membrane properties (i.e., contact angle and pore size). ECTFE coating decreased the surface roughness reducing, as a consequence, the hydrophobicity of the membrane. Moreover, increasing the ECTFE concentration and dip-coating time enabled the preparation of a thicker layer of ECTFE with low and narrow pore size that negatively affected the water transport. On the basis of the superior chemical resistance of ECTFE, ECTFE/PP composite hollow fibers could be considered as very promising candidates to be employed in membrane processes involving harsh conditions.
      PubDate: 2016-09-19
      DOI: 10.3390/coatings6030040
      Issue No: Vol. 6, No. 3 (2016)
       
 
 
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