SYNTHESIS OF MONODISPERSED SPHERICAL BETA-SILICON CARBIDE POWDER BY A SOL-GEL PROCESS

Monodispersed spherical β‐SiC powder was synthesized by heating spherical gel powder derived from the hydrolysis of a mixture of phenyltriethoxysilane and tetraethyl orthosilicate. The solution was prepared in a beaker and hydrolyzed by NH4OH without stirring. The monodispersed spherical gel powder of submicrometer size was obtained when the added amount of NH4OH was greater than 16 moles per mole of silane plus alkoxide, and it became monodispersed spherical β‐SiC powder by heat‐treating at 1500°C for 4 h in an Ar atmosphere. The SiC content of the powder was 92.6 wt%. Copyright © 1990, Wiley Blackwell. All rights reserved