Reactive Hot Pressing of ZrB2-SiC-ZrC Ultra High-Temperature Ceramics at 1800oC

A ZrB 2 -SiC-ZrC composite was prepared from a mixture of zirconium, silicon, and B 4 C via reactive hot pressing at a relatively low temperature (1800°C) for 60 min under 20 MPa in an argon atmosphere. The relative density was 96.8%, the micro-hardness (Hv10) was 16.7 GPa, and the fracture toughness was 5.1 MPa·m 1/2 . The presence of ZrC was helpful for the densification process and improved the mechanical properties of the composite. A model of the microstructure development of the composite was proposed to explain the phase distribution.