Effect of Si:C ratio on porosity and flexural strength of porous self-bonded silicon carbide ceramics

Abstract

Porous self-bonded silicon carbide (SiC) ceramics were fabricated at temperatures ranging from 1750 to 1850°C using SiC, silicon (Si), and carbon (C) powders as starting materials. The effect of the Si:C ratio on porosity and strength was investigated as a function of sintering temperature. It was possible to produce self-bonded SiC ceramics with porosities ranging from 36% to 43%. The porous ceramics showed a maximal porosity when the Si:C ratio was 2:1 regardless of the sintering temperature. In contrast, the maximum strength was obtained when the ratio was 5:1.