Preparation of mullite bonded porous SiC ceramics by an infiltration method
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A powder compact of α-SiC and α-Al2O3 was infiltrated with a liquid precursor of SiO2, which on subsequent heat treatment at 1500 °C produced a mullite bonded porous SiC ceramics. Results showed that infiltration rate could be estimated by using weight gain measurements and theoretical analysis. The bond phase was composed of needle-shaped mullite which was observed to be grown from a siliceous melt formed during the process of oxide bonding. The porous SiC ceramics exhibited a density and porosity of 2 g cm−3 and 30 vol%, respectively, and also a pore size distribution in a range of 2–15 μm with an average pore size of 5 μm. No appreciable degradation of room temperature flexural strength (51 MPa) was observed at high temperatures (1100 °C).
KeywordsCapillary Pressure Boehmite Liquid Precursor Mullite Formation Infiltration Curve
The authors would like to thank Mr. S.K. Dalui, Mechanical Property Evaluation Section, CGCRI, for his help in mechanical characterization. One of the authors (AD) expressed his appreciation to CGCRI (CSIR) for the Project Assistantship under Supra Institutional Project (SIP0023).