Thermal Shock Resistance of β'-Sialon-BN Composites Prepared by Pressureless Sintering and Reaction Bonding

Abstract

The thermal shock resistance of β'-Sialon-BN composites prepared by two different sintering processes, pressureless sintering (PLS) and reaction bonding (RB), were investigated with respect to the effect of hexagonal-BN content. The addition of BN showed increasing porosity for PLS body and crack extension for RB body. The water quenching thermal shock test showed that PLS body had better thermal shock resistance, especially for BN 20 mass%, than RB body. The results could be explained using Hasselman's theory, indicating that PLS bodies have shorter crack length with higher crack density.