Effects of ZrB₂ contents on the mechanical properties and thermal shock resistance of B₄C-ZrB₂ ceramics

B₄C-ZrB₂ ceramics with different ZrB₂ contents were fabricated using hot-pressing technique. The introduction of ZrB₂ greatly promotes the sintering process, and all B₄C-ZrB₂ samples achieve full densification. With the ZrB₂ content increasing from 10 to 40vol.%, the Vickers hardness ranges from 28.8 to 34.6GPa, the flexure strength ranges from 233.3 to 523.4MPa, and the fracture toughness ranges from 6.0 to 7.0MPam^1/2, respectively. The thermal shock properties of B₄C-ZrB₂ ceramics were also investigated using water quenching method. The critical thermal shock temperature difference (δT_c) for B₄C-10vol.% ZrB₂, B₄C-20vol.% ZrB₂, B₄C-30vol.% ZrB₂ and B₄C-40vol.% ZrB₂ ceramics are 293.5, 337.5, 365.4 and 373.5°C, respectively. Considering the ceramic should maintain a relatively high initial strength, B₄C-30vol.% ZrB₂ is found to exhibit the optimal thermal shock behavior.