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

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 ± 79 MPa) and fracture toughness (6.21 ± 0.25 MPa·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 ± 65 MPa) was obtained, much higher than that of ZrB2-SiC (587 ± 72 MPa) by single-step hot pressing at the same sintering temperature.