Improved thermal shock resistance of β-SiAlON/h-BN composite prepared by a precursor infiltration pyrolysis (PIP) route

Abstract β-SiAlON/h-BN composite with nearly full density was prepared by a precursor infiltration pyrolysis (PIP) combing pressureless sintering route, and its thermal shock resistance was evaluated by an indentation quenching method, experimentally. The prepared β-SiAlON/h-BN composite possesses equivalent apparent porosity and bulk density to the pressureless sintered β-SiAlON, which means the sintering and densifying were not hindered by the h-BN introduced by the PIP. The β-SiAlON/h-BN composite shows slight strength degrading and equivalent hardness compared with the β-SiAlON. After the quenching test, the crack propagation ratio of the β-SiAlON/h-BN is much lower, as little as only less than 1/60 of the β-SiAlON’s. It means that the thermal shock resistance of the β-SiAlON is improved significantly without obvious strength degrading by introducing of h-BN with the PIP procedure. High strength and excellent thermal shock resistance of the β-SiAlON/h-BN prepared in this work give it a great potential for application in high-temperature environments.