Enhanced mechanical properties, thermal shock resistance and ablation resistance of Si2BC3N ceramics with nano ZrB2 addition.

Abstract The mechanical properties, thermal shock resistance, and ablation resistance of nano ZrB 2 modified Si 2 BC 3 N ceramics were investigated. The results show that ZrB 2 stimulated microstructure evolution obviously. Therefore, the maximum strength and fracture toughness reach 559.6 MPa and 6.77 MPa·m1/2, which are improved by 61.0% and 29.4%, respectively. Furthermore, the residual strengths of 10 wt% ZrB 2 containing composites tested at 1000 ℃ retain 363.6 MPa, which is much higher than 97.7 MPa of pristine Si 2 BC 3 N ceramics. Besides, the ablation resistance of ZrB 2 modified Si 2 BC 3 N ceramics at 3000 ℃ is enhanced remarkably and the linear and mass ablation rates of ZrB 2 -10 are only 0.009 mm/s and 1.91 mg/s, respectively. The ablation in the ultra-high temperature zone is totally dominated by the ZrB 2 component, and the thermochemical erosion is determined by the oxidation resistance of ZrB 2 in the thermal affected zone. [ABSTRACT FROM AUTHOR]