Effect of thermal exposure on strength of ZrB2-based composites with nano-sized SiC particles

The effect of oxidation exposure on the room-temperature flexural strength of ZrB2-based composites with nano-sized and micron-sized SiC particles was investigated. The composites were densified by vacuum hot-pressing at 2000 °C for 60 min under a uniaxial pressure of 30 MPa. The flexural strength of as-received composites and after exposure in air at 1400 °C for 10 h was measured using the four-point bending test. The results show that the presence of intergranular and intragranular nano-sized SiC particles imparts a better oxidation resistance and improves the flexural strength of single-phase ZrB2 and ZrB2 ceramics with micron-sized SiC.