Synthesis of SiC Fine Particles by Gas-Phase Reaction Under Short-Time Microgravity

　SiC fine particles were synthesized by the gas-phase thermal decomposition of tetramethylsilane (Si(CH₃)₄) in hydrogen under microgravity of 10^-4G for 10 sec. Rapid heating to the temperature over 800℃ which is required for thermal decomposition of Si(CH₃)₄ under short-time microgravity was attained using a chemical oven where the heat of exothermic reaction of combustion synthesis of Ti-Al-4B composites was used as the heat source. Monodisperse and spherical SiC fine particles were synthesized under microgravity, whereas aggregates of SiC fine particles were synthesized under 1 G gravity. The SiC particles synthesized under microgravity(150-200 nm) were bigger in size and narrower in size distribution than those under 1 G gravity(100-150 nm).