Abstract
The imide powders of Si-C-N-H system were formed by liquid phase reaction in SiCl4-CH3SiC13-NH3 or SiCl4-(C2H5)2NH system in n-hexane and decomposed at 900°C in vacuum to amorphous powder of Si-C-N system. The powders were heat-treated in N2 at 1400-1800°C. Si3N4 was crystallized above 1500°C and SiC was formed at higher temperatures. The formation temperature of SiC lowered with an increase of the carbon content in the synthesis system. The SEM-EDX indicated that the detected carbon content was small, when Si3N4 phase was predominant, and increased according to SiC formation at high temperatures. This means that carbon may be included inside Si3N4 particles, reacting with Si3N4 to form SiC at higher temperatures. This results suggests that Si3N4-SiC composite can be fabricated from the Si-C-N amorphous powder by optimizing starting materials and heat treatment condition.
