Preparation of Silicon Carbide from Pyrolysis of Carbosilane Polymer

Abstract

The porous and crosslinked polycarbosilane with a powerful affinity for oxygen was obtained by the pyrolysis of polydimethylsilane in N₂ gas atmosphere. This polycarbosilane was converted to silicon carbide by heat-treating at the temperatures from 1200 to 1400°C in N₂ gas atmosphere, and quartz was formed as a by-product. The addition of polyvinyl butyral as a carbon source to polycarbosilane prevented quartz formation. The chemical analysis of silicon carbide showed that the ratio of Si to C was not theoretical but C content was larger than Si. As the temperature rose, the ratio of Si to C approached theoretical value, and free carbon content increased.