Subjects -> METALLURGY (Total: 59 journals)
Showing 1 - 10 of 10 Journals sorted alphabetically
Acta Metallurgica Slovaca     Open Access   (Followers: 2)
Advanced Device Materials     Open Access   (Followers: 6)
American Journal of Fluid Dynamics     Open Access   (Followers: 44)
Archives of Metallurgy and Materials     Open Access   (Followers: 9)
Asian Journal of Materials Science     Open Access   (Followers: 4)
Canadian Metallurgical Quarterly     Hybrid Journal   (Followers: 21)
Complex Metals     Open Access   (Followers: 2)
Energy Materials : Materials Science and Engineering for Energy Systems     Hybrid Journal   (Followers: 24)
Graphene and 2D Materials     Open Access   (Followers: 6)
Handbook of Ferromagnetic Materials     Full-text available via subscription   (Followers: 1)
Handbook of Magnetic Materials     Full-text available via subscription   (Followers: 2)
High Temperature Materials and Processes     Open Access   (Followers: 6)
Indian Journal of Engineering and Materials Sciences (IJEMS)     Open Access   (Followers: 11)
International Journal of Metallurgy and Alloys     Full-text available via subscription   (Followers: 2)
International Journal of Metals     Open Access   (Followers: 7)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 12)
International Journal of Mining and Geo-Engineering     Open Access   (Followers: 4)
Ironmaking & Steelmaking     Hybrid Journal   (Followers: 5)
ISIJ International - Iron and Steel Institute of Japan     Full-text available via subscription   (Followers: 26)
Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional’nye Pokrytiya (Proceedings of Higher Schools. Powder Metallurgy аnd Functional Coatings)     Full-text available via subscription   (Followers: 2)
JOM Journal of the Minerals, Metals and Materials Society     Hybrid Journal   (Followers: 35)
Journal of Advanced Joining Processes     Open Access  
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of Cluster Science     Hybrid Journal  
Journal of Heavy Metal Toxicity and Diseases     Open Access  
Journal of Iron and Steel Research International     Hybrid Journal   (Followers: 11)
Journal of Materials & Metallurgical Engineering     Full-text available via subscription   (Followers: 2)
Journal of Materials Processing Technology     Hybrid Journal   (Followers: 21)
Journal of Metallurgical Engineering     Open Access   (Followers: 4)
Journal of Sustainable Metallurgy     Hybrid Journal   (Followers: 3)
Materials Science and Metallurgy Engineering     Open Access   (Followers: 7)
Metal Finishing     Full-text available via subscription   (Followers: 20)
Metallurgical and Materials Engineering     Open Access   (Followers: 7)
Metallurgical and Materials Transactions A     Hybrid Journal   (Followers: 42)
Metallurgical and Materials Transactions B     Hybrid Journal   (Followers: 32)
Metallurgical and Materials Transactions E     Full-text available via subscription   (Followers: 2)
Metallurgical Research & Technology     Full-text available via subscription  
Metallurgical Research and Technology     Full-text available via subscription   (Followers: 8)
Metallurgy and Foundry Engineering     Open Access   (Followers: 3)
Mining, Metallurgy & Exploration     Hybrid Journal  
Powder Diffraction     Full-text available via subscription   (Followers: 1)
Powder Metallurgy     Hybrid Journal   (Followers: 35)
Powder Metallurgy and Metal Ceramics     Hybrid Journal   (Followers: 7)
Powder Metallurgy Progress     Open Access   (Followers: 5)
Practical Metallography     Full-text available via subscription   (Followers: 6)
Rare Metals     Hybrid Journal   (Followers: 3)
Revista de Metalurgia     Open Access  
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Revista Remetallica     Open Access   (Followers: 1)
Russian Metallurgy (Metally)     Full-text available via subscription   (Followers: 4)
Science and Technology of Welding and Joining     Hybrid Journal   (Followers: 8)
Soldering & Surface Mount Technology     Hybrid Journal   (Followers: 2)
Steel Times lnternational     Partially Free   (Followers: 19)
Transactions of the IMF     Hybrid Journal   (Followers: 14)
Transactions of the Indian Institute of Metals     Hybrid Journal   (Followers: 5)
Tungsten     Hybrid Journal  
Universal Journal of Materials Science     Open Access   (Followers: 3)
Welding in the World     Hybrid Journal   (Followers: 8)
Welding International     Hybrid Journal   (Followers: 11)
Вісник Приазовського Державного Технічного Університету. Серія: Технічні науки     Open Access  
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Metallurgical and Materials Transactions B
Number of Followers: 32  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1543-1916 - ISSN (Online) 1073-5615
Published by Springer-Verlag Homepage  [2656 journals]
  • Sulfurization Roasting Process of Nd 2 O 3 and Synthetic NdFeO 3 with
           Ferric Sulfate
    • Abstract: The environmental and economic recovery of rare-earth (RE) from NdFeB magnet waste is becoming increasingly important. In this study, the sulfurization possibility of two main RE-bearing phases of Nd2O3 and NdFeO3 in the fully oxidized NdFeB waste by ferric sulfate was evaluated. TG-DTA curves of the Nd2O3 and NdFeO3 sulfurization with 1.5 times of the theoretical Fe2(SO4)3·5H2O dosage showed that the temperatures range of Nd2(SO4)3 formation were 873 K to 963 K, and the starting temperature of Nd2(SO4)3 decomposition was ~ 1070 K. Specific experiments revealed by XRD and SEM-EDS analysis that Nd2O3 and NdFeO3 phases were successfully sulfated by Fe2(SO4)3·5H2O. The optimum roasting temperature was determined to be 973 K corresponding to the highest Nd leaching efficiency by the sulfurization of Nd2O3. At above 973 K, the decomposition of Nd2(SO4)3 resulted in the decrease of Nd leaching efficiency. Furthermore, the required roasting time and Fe2(SO4)3·5H2O dosage to obtain the same Nd leaching efficiency were different for the sulfurization of Nd2O3 and NdFeO3 at 973 K, and the sulfurization of NdFeO3 was more difficult than that of Nd2O3. Based on the results, an innovative method for recovering RE from NdFeB magnet waste was proposed.
      PubDate: 2021-05-03
       
  • Experimental Study of the Slag/Matte/Metal (Fe or Cu)/Tridymite Equilibria
           in the Cu-Fe-O-S-Si-(Ca) System at 1473 K (1200 °C): Effect of Ca
    • Abstract: A combined experimental and thermodynamic study has been carried out to determine the CaO effect on the equilibria between slag/matte/metal (Fe or Cu)/tridymite phases in the Cu-Fe-O-S-Si-Ca system at 1473 K (1200 °C). The experimental methodology included equilibration of the mixtures at high temperatures on substrates made from the primary phase, followed by rapid quenching of the samples and direct measurement of the condensed phase compositions using the Electron Probe X-ray Microanalysis (EPMA) technique. New experimental results have been obtained for fixed concentrations of CaO in slag phase (1.5, 6, 9, and 18 wt pct). All results have been plotted as functions of the copper concentration in the matte phase and provides information about the effect of CaO on the oxygen and sulfur concentration in the matte phase; the Fe/SiO2 ratio in slag; and dissolved copper and sulfur in slag. The experimental research is part of integrated experimental and thermodynamic study aimed to development and optimisation a thermodynamic database for copper-containing systems of non-ferrous metallurgy.
      PubDate: 2021-05-03
       
  • Post-mortem Ladle Shroud Analysis from the Casting of Al-Killed Steel:
           Microstructures and Origin of Alumina Clogging Deposits
    • Abstract: This work presents post-mortem microstructural analysis on the inner surfaces of single-use ladle shrouds of a ten-heat casting series of Ti-alloyed, Al-killed IF steel, in continuation of earlier work on the origin of alumina clogging formation in the casting system. It is found that ladle shrouds can be used as a representative sampler of materials exiting the ladle during the casting, which can be used to extract useful information about processes taking place in the shrouds and lower ladle during casting. All shrouds showed no ladle glaze emission but significant clog-like deposition of alumina. The alumina particles occur in two main forms (NMI embedded in the steel and alumina powder) and show the same two PDF populations (small Population I and coarse Population II) with the cross over at 5 µm, as the alumina particles found in the tundish clog of the same cast series. Detailed characterisation of inclusions in the shrouds revealed metal sub-inclusions containing Cr and Si, also similar to the tundish clogs. Thus, the hypothesis that the coarser population originates from the local oxidation of the steel in ladle bottom interface and ladle well region, including the well filler sand, is evidenced in this study. The fine Population I (often associated with dendritic and planar shapes) seen in the tundish clog, appears to be related to local carbothermic reaction in the ladle shrouds. Microstructures found on the surfaces on the shrouds are extensively shown and characterised.
      PubDate: 2021-05-03
       
  • Influence of the Gangue Compositions on the Reduction Swelling Index of
           Hematite Briquettes
    • Abstract: The effect of gangue compositions and the basicity (CaO/SiO2) on the RSI (reduction swelling index) of hematite briquettes was investigated using pure reagent briquettes. The results show that CaO can increase the RSI of the fired briquettes, while the MgO, Al2O3, and SiO2 can decrease the RSI of the fired briquettes. The RSI is related to the porosity and the mineral phases of the fired briquettes, and the morphology of metallic iron in the reduction process. The fired briquettes containing CaO present a higher porosity than that of the other briquettes, which is beneficial to increase the reduction reaction rate and promote the formation of metallic iron whiskers. With the increase of the porosity of briquettes, the RSI of briquettes increases.
      PubDate: 2021-05-03
       
  • Simulation and Application of Ruhrstahl–Heraeus (RH) Reactor with
           Bottom-Blowing
    • Abstract: To increase the refining efficiency of the Ruhrstahl–Heraeus (RH) reactor used in steelmaking, extra gas was blown into the molten bath through the bottom of the ladle. Both water experimental and numerical simulation models were established to analyze the flow field behavior to select the optimal bottom-blowing position and to study the effects of the bottom-blowing flow rate on the flow field of the molten bath, slag eye formation, and snorkel refractory materials. The results show that the recirculation flow rate increases and the mixing time decreases with an increase in the bottom-blowing flow rate. When blowing at the optimal position, the velocity of the molten steel in the ladle increases with increasing gas flow rate, and the low-velocity zone between the down-snorkel and ladle wall disappears, but the slag eye is easily formed. The simulation and experimental results were applied to an industrial 150 t RH reactor, where the optimal bottom-blowing flow rate and position improved the refining effect without forming a slag eye or having adverse effects on the snorkel refractory. To reduce the mass fraction of hydrogen to 2.0 ppm, the required processing time was shortened by 16.40 pct, and the dehydrogenation rate was increased by 19.51 pct.
      PubDate: 2021-04-30
       
  • Slag-Steel Emulsification on a Modified RH Degasser
    • Abstract: A new arrangement of RH snorkels is proposed in order to improve the slag metal interaction. According to this RHDeS design, the steel jet flowing down from the vacuum chamber discharges inside the slag layer. Physical modeling of a reactor following this concept was performed. Mixing times, circulation rates, and the mass transfer coefficient were evaluated as well as the droplet residence time. Mixing times and overall circulation are not very much affected by the modifications. However, the modification brings about a large and sustainable dispersion of slag (oil) in metal (water). The influence of this dispersion on de-S was assessed. A lumped kinetic parameter \( KA /v_{\text{w}} \) was evaluated in order to quantify the process kinetics. Kinetics can be improved by one order of magnitude. It is suggested that proper slag (amount and basicity) allied to this geometric modification could be fruitful to sulfur removal from deoxidized steel. Simulations show that sulfur removal with this RHDeS arrangement is expected to be higher than with schemes where de-S reagents are added in the vacuum chamber.
      PubDate: 2021-04-30
       
  • Reaction Rate Analysis of Manganese Ore Prereduction in CO-CO 2 Atmosphere
    • Abstract: Variations in energy efficiency and climate gas emissions in production of manganese ferroalloys are largely related to the solid-state reduction of the manganese ores used as raw material in the production. The gas-solid reduction is known to be dependent on the ore characteristics, making information on the factors governing the kinetics crucial. A reaction rate analysis of thermogravimetric data obtained for the reduction of Comilog and Nchwaning manganese ores in CO-CO2 atmosphere was performed. Experimental variables were CO partial pressure, ore particle size, temperature regimes (isothermal/non-isothermal), as well as heating rate for non-isothermal experiments. The effects of particle size, CO-concentration, and temperature on the reaction rates were quantified. It was found that the reduction rate of both ores was proportional to the inverse average particle size. Different sensitivities towards the CO-concentration in the gas feed was determined, where the rate of Comilog-ore was proportional to \( p_{\text{CO}}^{0.7} \) , and Nchwaning to \( p_{\text{CO}}^{1.5} \) . The activation energy of Comilog ore was estimated to be 17 kJ/mol, whereas 63 kJ/mol was found for Nchwaning ore.
      PubDate: 2021-04-29
       
  • Statistical Analysis of the Inclusions in Rare Earth-M ( M = Ca and Ti)
           Treated Steel
    • Abstract: The size, quantity, morphology and structure of inclusions in steel treated with rare earth (RE) with different deoxidizers (calcium and titanium) were studied. The difference between automatic and manual inclusion statistical analyses was investigated. The results showed that: RE tended to refine the inclusions and increase the number density of the inclusions in steel. When combined with RE, calcium and titanium could reduce the number densities of inclusions. The mean diameters of the inclusions in the RE-treated steel and RE-titanium-treated steel were close, and smaller than that in the RE-calcium-treated steel. Calcium and titanium reduced the mean aspect ratio of inclusions in the RE-treated steel. RE particles and MnS formed random composite inclusions when only RE was added. In RE-calcium-containing composite inclusion, the amount of MnS was very low. For RE-titanium-treated steel, almost all titanium formed composite inclusions with RE. The inclusion automatic analysis (IAA) system showed better performance in counting the content percentage of inclusions. However, for determining the inclusion number in RE-containing steel and size statistical analysis, manual inclusion statistical analysis was superior.
      PubDate: 2021-04-29
       
  • The Efficacy of a Three-Dimensional Static Liquid–Vapor Interface Model
           to Calculate the Static Liquid Holdup of a Packed Bed
    • Abstract: When liquid flows in an operating packed bed, some volume of the liquid remains in the bed at any instant of time. This is known as total liquid holdup. When the liquid flow is stopped, some portion remains static in the bed and the rest drains out. The first portion of the total liquid holdup is known as the static liquid holdup. The extent of the static liquid holdup affects mass transfer, heat transfer, permeability, as well as productivity of a packed bed reactor. Experimental and fundamental research has been performed to calculate the extent of static liquid holdup for last several decades. Many empirical correlations have been developed and mathematical models have been made in pursuit of quantifying this. However, significant difference in the experimental observations and modeling results can still be seen in the literature. In this work, a fundamental building block of a packed bed, i.e., a two-sphere contact, has been taken as the investigation domain. Experiments have been performed to understand how liquid films are formed, their shapes and variation of maximum static film volume before dripping, with respect to inclination for specific contact angles. Dripping involves formation and draining of droplets, and a volume remaining at the contact after dripping; these are measured for various inclinations of the sphere contact axis. Notionally, static liquid holdup is the volume of the liquid that can be held at the two-sphere contacts due to the interplay between static forces namely the surface tension and gravitational force. Hence, the mathematical model incorporating only static forces to capture the three-dimensional liquid shape at the two-sphere contacts, developed in a previous work of our group, is used in this work, and it is shown that the maximum volume of liquid before the liquid dripping can be very well captured for various inclinations. On the other hand, the remaining volume calculated from the mathematical model, with the assumption of quasistatic droplet detachment, results in much underprediction. When the two-sphere experimental values are extended to packed bed situations, it can be shown that the static liquid holdup calculated from the remaining volume after dripping matches are closer to the packed bed experimental values, whereas static liquid holdup calculated from maximum volume leads to overprediction.
      PubDate: 2021-04-28
       
  • Thermodynamic Analysis of TiN Precipitation in SWRH92A High Carbon Tire
           Cord Steel Under the Influence of Solute Micro-segregations During
           Solidification
    • Abstract: The precipitation of TiN inclusion during the solidification of SWRH92A high carbon tire cord steel has been thermodynamically calculated. The influence of solute micro-segregations calculated by Ohnaka and Clyne–Kurz models, respectively, on the thermodynamic parameters is considered. The TiN precipitation module is coupled with the Ti and N micro-segregations when the condition of TiN precipitation is satisfied. Furthermore, the TiN growth is predicted based on the thermodynamic calculation results. The results first show that the solute elements of molten steel segregate to different extents during solidification. The carbon concentration increases most significantly by about 1.8 wt pct due to its highest original content. By coupling TiN precipitation module with solute micro-segregation module, the segregated ratios of Ti and N decrease after the TiN inclusion starts precipitating. With cooling rate increasing from 0.17 to 1.67 K/s, TiN precipitation starts earlier, but the TiN particle size decreases from about 10 to about 3 μm. The TiN inclusion sizes calculated in the Ohnaka and Clyne–Kurz model cases are close and well validated by the metallographic images of TiN inclusions and the statistical data of TiN particle size distribution in high carbon tire cord steels. This agreement encourages the proposed calculation method and provides guidance for the future thermodynamic studies of nonmetallic inclusions of steel.
      PubDate: 2021-04-27
       
  • Influence of Silicon Carbide on Shear-Thinning Behavior of CaO-SiO 2 -CaF
           2 -Based Mold Fluxes
    • Abstract: To control the shear property of a calcium silicate mold flux, we incorporated carbon (C) into it in the form of SiC. We measured the flux’s viscosity using a rotationary viscometer to quantify its shear-thinning behavior and analyzed its structure to determine its degree of polymerization. Silicon carbide had the strongest shear-thinning property at C content = 1 wt pct and had the highest shear-thinning property ever achieved in a mold flux. The degree of shear-thinning property for silicon oxy-carbide glass followed the Oswals-De Waele power law model. This mold flux will improve the quality of continuously-cast steel by providing appropriate lubrication between the mold wall and the steel shell.
      PubDate: 2021-04-26
       
  • A Review of Ferroalloy Tapping Models
    • Abstract: Tapping is an important furnace operation in the ferroalloy industry and poses a number of complex and coupled challenges of both practical and economical importance. Owing to the hazardous high-temperature conditions surrounding the tap hole, the application of various modeling techniques allows for development and acquisition of both scientific and engineering knowledge of the process through physical or numerical proxies. In this review, earlier work on modeling of ferroalloy tapping is summarized and main principles of the tapping process and multiphase interaction of slag and metal are discussed and summarized. The main focus is on drainage of slag and alloys, but some attention will also be given to metal loss, metal overflow and health, safety and environment. Our review shows that although considerable progress has been made in computational capability over the last decades, However, it is clear that research and development in the field of ferroalloy furnace tapping remains at a relatively nascent stage. The most progress up to date has happened in the area of so called reduced-order models. Such models are robust and simple, and may be easily fitted to process data from a particular operation in order to develop tailored solutions. Such models are more easily combined with software and instruments, ultimately enabling improved automation, process control and ultimately improved tapping consistency.
      PubDate: 2021-04-23
       
  • A Numerical Study on Blowing Characteristics of a Dynamic Free Oxygen
           Lance Converter for Hot Metal Dephosphorization Technology Using a Coupled
           VOF-SMM Method
    • Abstract: Numerical simulations are performed to explore the basic blowing characteristics of a dynamic free lance converter applied to hot metal dephosphorization technology, in which the sliding mesh model (SMM) is used to regulate the rotation motion of the top lance and the volume of fluid (VOF) model is inducted to simulate flows of gaseous oxygen, liquid slag and metal. The fundamental phenomena such as the motion of phase interfaces, slag–metal emulsion and mixing, and shape and magnitude of the velocity field inside the slag–metal bath are predicted reasonably well, and effects of lance designs including the lance twist angle and rotation speed on the blowing characteristics are evaluated. The results show that the rotation motion of the lance improves the flows inside the molten bath and induces remarkable circumferential and swirl flows around the hot spot. Such flows change the splashing mode and accelerate the dispersion of the splashed metal inside the slag layer, consequently producing a quite uniform distribution of metal phase in emulsion and promoting slag–metal emulsion and mixing. The slag–metal emulsion is strengthened when increasing the lance twist angle, but achieves its minimum at the lance rotation speed of 1.0472 rad/s. The effects of the lance twist angle and rotation speed on flow fields inside the molten bath vary with the bath depth.
      PubDate: 2021-04-22
       
  • Experimental Study on the Chemical Stability of Phosphate-Bonded Al 2 O 3
           -Based Ceramic Foam Filters (CFFs)
    • Abstract: Production of high-quality aluminum products requires an extensive melt treatment process, even more so with the increasing focus on recycling and sustainability. Filtration is a commonly used process segment for removal of non-metallic inclusions in aluminum, and ceramic foam filters (CFFs) are often used as the filtration media. In the present study, the chemical stability of phosphate-bonded Al2O3-based CFFs has been investigated. Three filters with different chemical compositions have been submerged into pure aluminum (with traces of Mg) and in an aluminum-magnesium melt (~ 2 wt pct Mg) at 730 °C. In addition to filter characterization before and after exposure to molten metal, using various imaging and X-ray techniques, the melt itself was analyzed by spark optical emission spectroscopy. The generation of phosphine gas was also measured by the use of Dräger tubes, and thermodynamic calculations performed using FactSage™. The phosphate-bonded filters were observed to react with the magnesium present in the molten aluminum even at very low magnesium concentrations (0.00035 wt pct), and as the magnesium concentration increased the severity of the degradation became more and more evident. The exposure time proved to have detrimental effect on the filter structure, with pieces of the filter struts broken off causing melt contamination. Severe filter degradation also resulted in color changes with accompanying diffusion of magnesium and phosphorus to and from the filter, respectively. Moreover, phosphine gas was released in amounts exceeding recommended exposure limits when the filter came in contact with the humidity in the air after testing. Good agreement was established to exist between the results from the thermodynamic calculations performed and the experimental results.
      PubDate: 2021-04-22
       
  • Production Rate of SiO Gas from Industrial Quartz and Silicon
    • Abstract: The production rate of SiO gas from industrial quartz and silicon has been investigated by isothermal heat treatment experiments. Mixtures of silicon and different quartz samples have been heated to temperatures ranging from 1650 °C to 1950 °C and held for 30 to 120 minutes before cooling. The weight loss of each sample has been correlated to degree of reaction and a model for the reaction rate of Si + SiO2 has been developed based on these values. Five different types of industrial quartz were used in the experiments. No significant difference was found in their reaction rate, even though there are large variations in impurity content, melting rate, decrepitation, and phase transformation rate of each sample. Further on, it is shown that the reaction rate of silicon mixed with various types of quartz can be described by an Arrhenius equation: \({{\rm {d}}\alpha /{\rm {d}}t = k_0 \, A \, {\rm {exp}} (- Q / RT)}\) . A reaction constant (k0) equal to \({6.25 \, 10^8 {\rm {g}}\, {\rm {s}}^{-1}\, {\rm{m^{-2}}}}\) and an activation energy (Q) equal to \({557\, {\rm {kJ \, mol^{-1}}}}\) were obtained by linear regression. The degree of reaction ( \({\alpha }\) ) is shown to be increasing with available reaction area, temperature, and time.
      PubDate: 2021-04-21
       
  • Research on Inclusion Evolution during Re-Heating Process in Ti-Zr
           Deoxidized Low Carbon Steel
    • Abstract: The effect of the re-heating process on inclusion evolution in Ti-Zr deoxidized low carbon steel was investigated using high-temperature resistance furnace, high-temperature confocal laser scanning microscope, scanning electron microscope with energy-dispersive spectrometer, and electron probe microanalysis with wavelength-dispersive spectrometer. The results indicated that compared with as-cast sample, the entire inclusion characteristics in heated samples were affected by the couple effect of heating temperature and holding time. As temperature and holding time increased, the shape of the Ti-Zr oxide changed from an irregular, curved surface to a smooth, spherical surface owing to the outermost layer being enveloped by liquid inclusion of Si-Mn-Al oxide. Additionally, the Ti-Zr oxide composition distribution changed from homogeneous to heterogeneous during heating in the range of 1100 °C to 1400 °C for 2 hours. Finally, different cooling modes had a significant influence on the inclusion characteristics. Compared with cooling by direct water quenching, the process of initial cooling to 1000 °C with furnace cooling and followed by water quenching could increase the number density of nitrides and sulfides, as well as change the unstable oxide to an effective oxide by precipitation of TiN on the surface.
      PubDate: 2021-04-21
       
  • Facile Electrodeposition of Ti 5 Si 3 Films from Oxide Precursors in
           Molten CaCl 2
    • Abstract: It is hard to produce dense refractory Ti5Si3 films at low temperature because of the extremely high melting point (2130 °C) of Ti5Si3. Herein, we report the facile electrodeposition of Ti5Si3 films from TiO2 and SiO2 in molten CaCl2-CaO at 850 °C. Crystalline Ti5Si3 films with tunable film thicknesses and morphologies can be obtained in a controlled manner. The dissolution-electrodeposition processes were systematically investigated by cyclic voltammetry (CV), in-situ X-ray diffraction (XRD), in-situ Raman analysis, etc., and the synthesized Ti5Si3 products were characterized by electron backscattered diffraction (EBSD), transmission electron microscopy (TEM), three-dimensional atomic probe (3DAP), etc. The results show that the morphology of the products can be significantly influenced by current density. By controlling current density at the range from 10 to 25 mA cm−2, Ti5Si3 products with different morphologies, i.e., dendritic particles, dense films, and porous powders, can be obtained in a controlled manner. Besides, Ti, Si atoms uniformly distributed in the films. The reaction mechanism of the formation of Ti5Si3 film was also proposed, which can be summarized as three periods: CaO-assisted dissolution of SiO2 and TiO2, the electrodeposition of Si and Ti, and the formation of stable Ti5Si3 phase. The CaO-assisted dissolution-electrodeposition process may provide a promising strategy for the production of Ti5Si3 alloy films and powders.
      PubDate: 2021-04-21
       
  • The Influence of Liquid–Solid Interface Position and Shape on the
           Electromagnetic Forcing Parameter During Horizontal Solidification
    • Abstract: The forcing parameter is an important value for determining the solidification conditions under electromagnetic impact. This parameter tends to change and affect the solidification conditions. The aim of this work is to investigate the influence of the liquid–solid interface position and deformation on the forcing parameter. Electromagnetic analysis by the finite element method, validated experimentally, was used as the main research tool. Horizontal solidification in the presence of a traveling magnetic field installation was chosen as the experimental setup. Various interface deformations were investigated, as well as its propagation. As a result of the calculation, the electromagnetic (EM) forcing parameter functions were obtained. It was determined that the liquid–solid interface propagation causes significant attenuation of the forcing parameter, as well as interface slope. The results were analyzed and approximated by analytical functions. These functions can be easily used to determine values for various solidification conditions and stages.
      PubDate: 2021-04-21
       
  • Review of the Liquid Metal Extraction Process for the Recovery of Nd and
           Dy from Permanent Magnets
    • Abstract: Neodymium (Nd) and dysprosium (Dy) based rare earth (RE) magnets are critical to green economy due to their vital role in permanent magnet applications such as electric motors and generators. The accumulating RE magnet waste in the form of end-of-life products (EoL), criticality of supply-demand, and the huge environmental costs associated with RE mining translated into an increased focus on RE recycling processes in the last decade. Environmentally friendly pyrometallurgical techniques were developed as an alternative to the traditional hydrometallurgical route due to the generation of large amounts of waste in hydrometallurgy. Liquid metal extraction (LME) is a promising pyrometallurgical technology as it has the ability to handle a wide variety of scrap feed materials, from swarf to ingots; to produce clean material with minimal impurities; and to allow the separation of metallic species without metallothermic reduction. So far, magnesium, silver, copper, and bismuth have been used as LME agents while exploration of other possibilities is ongoing. This article presents a systematic review of previous studies on the extraction agents in terms of the reaction mechanisms, behavior of the RE elements, extraction efficiencies, and the formation of intermetallic compounds during the process.
      PubDate: 2021-04-20
       
  • Analysis of Surface Tension and Viscosity of Liquid Metals
    • Abstract: The surface tension γ and the dynamic viscosity η of liquid alkali, alkaline earth, and transition metals at the melting point have been investigated. A physical interpretation of γ and η, as well as γ·η−1 and η2·γ−1, is given using surface density, thermal impulse, and the thermal length scale. Dimensionless surface tension and dimensionless dynamic viscosity at melting point are obtained, and excess entropy is calculated from the universal scaling law.
      PubDate: 2021-04-20
       
 
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