Cyclic Thermal Shock Resistance of Several Advanced Ceramics and Ceramic Composites

The cyclic thermal shock behavior of two Si3N4 ceramics, two SiC‐whisker‐reinforced alumina composites (Al2O3/SiCw), a SiC‐particulate‐reinforced alumina (Al2O3/SiCp), and an alumina continuously reinforced with SiC fibers (Al2O3/SiCf) composite has been studied. Specimens were repeatedly quenched from 1473 K into a fluidized bed with a heat transfer coefficient of 1400 W/(Km2) [250 Btu/(hft2F)]. The thermal shock damage was assessed by room‐temperature flexure strength measurements. Si3N4 and Al2O3/SiCp showed no noticeable damage after 100 cycles, whereas Al2O3/SiCw and Al2O3/SiCf degraded substantially. The experimental results are discussed and rationalized in terms of finite element simulations and microstructural observations. Our analysis suggests that the thermal shock performance of other materials may be estimated from comparisons with the present work.