ZrB2–SiC/ZrSi2 ceramics containing 30 vol% carbon fiber (Cf) additive were fabricated by hot pressing at low temperature (1500 ℃) using submicron
ZrB2 powders, and their microstructural evolution and performance were investigated. The
addition of SiC or ZrSi2 significantly reduced the onset sintering temperature and enhanced the densification
of ZrB2. ZrB2–ZrSi2–Cf showed poor performance owing to the serious fiber degradation, while the fiber degradation
was effectively inhibited in ZrB2–SiC–Cf resulting in high fracture toughness, substantial fiber pull-out, and non-brittle
fracture mode for such material. The critical thermal shock temperature difference
of ZrB2–SiC–Cf was up to 741 ℃, significantly higher than those of ZrB2–SiC/ZrSi2 and ZrB2–ZrSi2–Cf. Moreover, this composite displayed a good oxidation resistance at 1500 ℃ in air.