Effects of silicon particle size on microstructure and permeability of silicon-bonded SiC ceramics

Abstract

Porous silicon-bonded silicon carbide with tailored pore structure was prepared from silicon carbide, silicon, carbon, and boron powders as starting materials. Three different kinds of silicon particle sizes were used as pore formers, namely, fine (2.6μm), intermediate (12.9 μm) and coarse (169.8μm) while sintering temperatures varied from 1600 to 1800°C. These different processing conditions affected the characteristics of the prepared silicon-bonded silicon carbide (SBSC) which showed densities ranging from 1.65 to 1.95g/cm3. Flexural strengths and gas permeability showed an inverse proportion, up to 70MPa, 3.18 × 10-12 m2, respectively. Finally the effect of different silicon particle size and sintering temperatures on the gas permeability of silicon-bonded silicon carbide has been discussed. © 2012 The Ceramic Society of Japan.