Normalized evaluation of thermal shock resistance for ceramic materials

A normalized method for evaluation of thermal shock resistance for ceramic materials was proposed. A thermal shock resistance index (TSRI), Г, in the range of 1 to 100, was introduced, based on a normalized formula obtained directly by a simple testing process of determining the changes in flexural strength before and after thermal shock cycles. Alumina ceramic was chosen as the model material and its thermal shock behavior was investigated systematically by water quenching. Based on the experiments on alumina ceramic, the thermal shock behaviors of other 19 types of ceramic materials ranging from porcelain, refractory ceramics to advanced ceramics including structural and functional ceramics were also evaluated, and their TSRIs, Γ, were derived. The dependence of Г on the coefficient of thermal expansion (CTE) of the materials was plotted, and it revealed that CTE is the most critical factor in affecting the thermal shock resistance for various ceramic materials. The effect of other factors such as porosity and fracture toughness on the index was also discussed.