Solid-Phase Synthesis of Silicon Carbide Powders from Silicon and Carbon Powders

On the basis of analysis of diffusion processes, a theoretical justification for the possibility of synthesizing silicon carbide from a mixture of carbon black and silicon powders at temperatures below 1600°C is presented. Experimental confirmation of this possibility is obtained during solid-phase synthesis in vacuum for 8 h at a temperature of 1400°C. With a shorter sintering time, incomplete reaction of silicon carbide synthesis is observed. The synthesis conditions are investigated and the parameters are identified under which the initial powder mixture completely transforms into silicon carbide. Electron microscopy and X-ray diffraction analysis are used to study the microstructure and phase composition of the materials. The finished compacts have a uniform submicron microstructure with a grain size of less than 1 μm.