Effect of alumina content on flexural strength of porous mullite-bonded silicon carbide ceramics

Porous mullite-bonded SiC ceramics were fabricated from SiC and Al2O3 powders. The mullite-bonding phase was in situ synthesized by the reaction between the oxidation-derived SiO2 and alumina. The effects of the alumina content, sintering temperature, and sintering time on the microstructure, porosity, and flexural strength were investigated. The process developed in this study offers substantial flexibility for producing porous mullite-bonded SiC ceramics whereby porosity and flexural strength can be effectively controlled. It is demonstrated that the adjustment of the alumina content and the sintering temperature enable the possibility of tailoring the microstructure, porosity, and strength of the manufactured porous mullite-bonded SiC ceramics. The present results suggest that the proposed novel processing technique is suitable for the manufacture of porous mullite-bonded SiC filters with improved strength.