Effect of annealing treatment on mechanical properties of a ZrB2–SiC–graphite ceramic

The ZrB2–SiC–graphite (ZSG) ceramic was annealed at 1600, 1700 and 1800 °C for different times, respectively. It was revealed that the annealing treatment is favorable to increase the interface bonding and relative density, and to decrease the thermal residual stress, to result in the crimp of the graphite flake. It was the optimal annealing treatment process conditions of 1700 °C and 90 min according to the best combination of the mechanical properties. To compare the mechanical properties of the specimen before the annealing treatment, the hardness, strength and toughness of the specimen annealed at 1700 °C for 90 min were enhanced by 20.6% and 20.2%, decreased by 8.2%, respectively.