In this study, we evaluated the effects of acid leaching on the properties of Cr powder synthesized using self-propagating high-temperature synthesis (SHS). Cr powder was synthesized from a mixture of Cr2O3 and magnesium (Mg) powders using the SHS Process, and the byproducts after the reaction were removed using acid leaching. The properties of the recovered Cr powder were analyzed via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), particle size analysis (PSA), and oxygen content analysis. The results show that perfect selective leaching of Cr is challenging because of various factors such as incomplete reaction, reaction kinetics, the presence of impurities, and incompatibility between the acid and metal mixture. Therefore, this study provides essential information on the properties under acidic conditions during the production of high-quality Cr powder using a self-propagating high-temperature synthesis method.
Due to their unique properties, tungsten borides are good candidates for the industrial applications where certain features such as high hardness, chemical inertness, resistance to high temperatures, thermal shock and corrosion. In this study, conditions were investigated for producing tungsten boride powder from tungsten oxide(WO3) by self-propagating high-temperature synthesis (SHS) followed by HCl leaching techniques. In the first stage of the study, the exothermicity of the WO3-Mg reaction was investigated by computer simulation. Based on the simulation experimental study was conducted and the SHS products consisting of borides and other compounds were obtained starting with different initial molar ratios of WO3, Mg and B2O3. It was found that WO3, Mg and B2O3 reaction system produced high combustion temperature and radical reaction so that diffusion between W and B was not properly occurred. Addition of NaCl and replacement of B2O3 with B successfully solved the diffusion problem. From the optimum condition tungsten boride(W2B and WB) powders which has 0.1~0.9 um particle size were synthesized.
Preparation processing of sintered silicon nitride ceramics was emphatically investigated with Self-Propagating High-Temperature Synthesis (SHS) of silicon nitride prepared by ourselves as raw material. The results indicate that good sinter ability can be obtained with cheaply SHS of silicon nitride preparing silicon nitride materials. The cost of silicon nitride materials will be lowered.
In the present study, equiatomic porous TiNi shape-memory alloys have been successfully prepared by self-propagating high-temperature synthesis (SHS) using elemental titanium and nickel powders. The porous TiNi alloys thus obtained have an open porous structure with about 64 vol.% porosity, and the pore size is about 1.8 mm. The effect of preheating temperature on the microstructure have been investigated. It is found that the pore size increases with increasing preheating temperature. Moreover, the preheating temperature was shown to have a significant effect on the microstructrue of the SHS-synthesized porous TiNi shape memory alloys.