Microstructure and thermal shock behavior of ZrB2–SiC–graphite composite

A water-quenching technique was adopted to evaluate the thermal shock behavior of hot-pressed ZrB2–SiC and ZrB2–SiC–graphite composites in an air atmosphere. The strength retention of the two kinds of composites was measured after varying temperature (ΔTc) up to 1000 °C. Monolithic ZrB2–SiC showed rapidly drop in flexural strength above ΔT of 400 °C, however the critical thermal shock temperature difference (ΔTc) is enhanced by adding graphite, and the ZrB2–SiC–graphite composite showed a higher retained strengths up to 1000 °C. The main reasons for a great improvement of thermal shock resistance (TSR) were also discussed and analyzed.