Fabrication of non-oxide ceramic powders by carbothermal-reduction from industrial minerals

Abstract

The most promising method for obtaining a large variety of non-oxide products having important technical uses is carbothermal-reduction reaction (CRR). By using this procedure, SiC and ZrC/SiC powders are obtained from diatomaceous earth and zircon powder. In this way the synthesized powders are obtained at a relatively low temperature due to good homogenization. Starting C/ZrSiO4 admixtures having different molar ratios (3:1, 4:1, 5:1 and 7:1) and C/SiO2 having ratios 1:1, 3:1, 4:1, and 7:1 were heated at temperatures between 1300 and 1600°C in a controlled Ar flow atmosphere. The phase evolution was a function of the raw materials molar ratios and sintering temperature. The optimal parameters for the synthesis of SiC and ZrC/SiC powders were obtained. The results obtained by EDS analysis are in good agreement with those obtained by XRD analysis for the synthesized carbide powders.