Preparation and properties of zirconium diboride-based ultra-high temperature ceramics

Zirconium diboride (ZrB₂)-based ultra-high temperature ceramics (UHTC) reinforced by silicon carbide (SiC) particles were prepared by hot press sintering at 1950°C for 1 h under 20 MPa pressure in an argon flow. The relative density of ZrB₂/SiC_p composites increased with the content of SiC addition, and reached 100% when 15% (in volume) SiC particles were added. The bending strength and toughness of the composites also increased with increasing SiC amount, and reached values of 646 MPa and 8.52 MPa·m^1/2, respectively, at 15% SiC addition. Furthermore, the addition of SiC particles improved the resistance to oxidation/ablation of ZrB₂/SiC_p composites.