Abstract
In relation to the synthesis of SiC powder, the mechanism of the pyrolysis of polycarbosilane-SiO2 mixture was investigated. Using mixtures with various mass ratio of polycarbosilane to Si02, the reaction rate was determined by thermogravimetry at temperatures from 1773 K to 1973 K under an argon atmosphere.
The content of SiC in the powder obtained by the pyrolysis of polycarbosilane is 57%. The addition Of SiO2 to polycarbosilane increases the content of SiC. The powder of 83% SiC was prepared from the mixture containing 15%Si02 at 1973 K.
Si02 powder reacts with amorphous carbon in polycarbosilane to produce SiO and SiC. It is considered that the reaction rate is controlled by the chemical process at the surface of Si02 particle.
