Preparation of ZrB2-SiC ceramics by single-step and optimized two-step hot pressing using nanosized ZrB2 powders

•Nanosized ZrB2 powders were used to fabricate ZrB2-SiC ceramics.•High strength ZrB2-SiC ceramic was obtained by hot pressing at 1800°C.•An optimized two-step hot pressing method was designed for preparation of ZrB2-SiC ceramic at low temperature. ZrB2-SiC ceramics were prepared by single-step hot pressing in the temperature range of 1500∼1800°C using nanosized ZrB2 powders. Dense ZrB2-SiC with high flexural strength (1044±79MPa) and fracture toughness (6.21±0.25MPa·m1/2) was obtained at 1800°C. An optimized two-step hot pressing process was designed and showed great advantages in fabricating of ZrB2-SiC ceramic with a high relative density (>98%) at low temperature. Furthermore, a high flexural strength (901±65MPa) was obtained, much higher than that of ZrB2-SiC (587±72MPa) by single-step hot pressing at the same sintering temperature.