PREPARATION OF SiC-AlN COMPOSITE POWDERS BY INORGANIC SOL-GEL PROCESSING
(Materials Science&Applied Chemistry Institute, Hunan University, Changsha 410082, P. R. China)
Abstract: SiC-AlN composite powders were prepared with silica sol, alumina sol and carbon black by sol-gel processing. The particle size of the powders usually ranged in 50~100nm and showed a slight increase with the increase of AlN content. In the carbothermal carbide/nitride process of Si-Al-O-C-N system, an intermediate product Si3Al3O3N5(sialon) appeared at 1 300℃and gradually decomposed into SiC and AlN at higher temperatures. However, Si3N4was not observed during the synthesizing process. SiC was obviously dissolved into AlN and resulted in the formation of SiC-AlN solid solution over 1 500℃.
Key words: silicon carbide aluminium nitride sol-gel