An aqueous polymer quenching medium for instantaneous thermal shock cooling rate study of ceramic materials

Abstract

An aqueous polymer quenching technique combing with a thermocouple real-time temperature acquisition technique were adopted to evaluate the thermal shock resistance of a hot-pressed ZrB2–SiC–graphite composite. The thermal shock behavior of the composite at different testing temperatures could be controlled and adjusted through varying the polymer concentration in the aqueous quenching solution. Experimental data showed that the critical maximum instantaneous thermal shock cooling rate at different testing temperatures was a constant value of 500 °C s−1(ν(max)c), and surface microcracks were assigned to the thermal shock failure. Heat transfer coefficient (h) gradient in samples, surface generated under two different quenching media, i.e. water and aqueous silicone oil solution, resulted in different tendency of decrease in strength. Thermal shock failure was presumed to be related to not only the body temperature gradient but also the surface h gradient in samples to produce thermal stress damage. The results indicate a promising method for studying the thermal shock resistance of ceramic materials.