Evaluation of Thermal Shock Resistance of Ceramics by Up-Shock Method and Water-Quench Method.

Abstract

An up-shock method was proposed as a new technique for estimating the thermal shock resistance of ceramics. The method uses a disk-shaped specimen which is heated by infrared ray and by a constant heat flux at the central area. This technique enables an evaluation of thermal shock strength, Rc, directly from the power charge, despite the fact that Rc consists of some of the properties of the tested material. In this paper, the thermal shock resistance of Al2O3 and Si3N4 are estimated by both the up-shock method and the improved water-quench method which was presented earlier. The results of the infrared radiation heating method show that the thermal shock strength of Si3N4 was 7 times as high as Al2O3's one. In the water quench method the heat transfer coefficient of water was indispensable for the quantitative estimation. In this study we show that the up-shock method is more suitable for the evaluation of the thermal shock resistance for ceramics.