Carbon Dioxide laser Synthesis of Ultrafine Silicon Carbide Powders from Diethoxydimethylsilane

Ultrafine SiC powders have been synthesized from diethoxydimethylsilane by laser-induced vapor-phase reactions. The powders produced under different flow rates of the reactant vapor have been characterized by chemical analysis, transmission electron microscopy, infrared spectroscopy, and X-ray diffractometry. The results show that the powders are less than 30 nm in average particle diameter, uniformly distributed, spherical in shape, and amorphous. The oxygen and free carbon of the powders vary with the vapor flow rate of the reactant. Annealing of the powders at 1,873 K in nitrogen for 1 h results in a complete transformation from amorphous SiC to [beta]-SiC and a small amount of [alpha]-SiC.