Abstract
An infrared radiation heating method is used to evaluate the thermal shock fracture toughness of three types of silicon nitride, including new material that has quite high thermal conductivity. This paper discusses how relevant thermal shock parameters should be estimated both as physical properties of materials and as a function of temperature. The temperature and stress distributions within a disk and the stress intensity factors for a disk with an edge crack are analyzed numerically in relation to the temperature-dependent thermal properties. Experimental results show that the highest thermal shock fracture toughness is obtained for the material that has the highest thermal conductivity.