Thermal shock behavior of ZrB2–SiC ultra-high temperature ceramics with addition of zirconia

Thermal shock behavior of ZrB2–10 vol%SiC ultra-high temperature ceramics with addition of ZrO2 was investigated by means of water-quenching as well as the finite element analysis. Optimal residual strength and critical temperature difference were obtained from ZrB2–10 vol%SiC ceramic added by 10vol%ZrO2. Simulated results revealed that ZrB2–10 vol%SiC–10 vol%ZrO2 provided the lowest thermal stress and stress intensity factor during thermal shock, which confirmed the experimental data. Such improvement in thermal shock resistance compared with ZrB2–10 vol%SiC was primarily ascribed to the improved toughness by the addition of ZrO2. Besides, appropriate phase transformation of ZrO2 during quenching was further beneficial to resist the thermal shock.