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

•ZrB2 promoted the densification of B4C based ceramics during hot pressing.•The Vickers hardness, flexural strength and fracture toughness were analyzed.•BZ3 ceramic had the best thermal shock resistance for engineering applications.

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 40 vol.%, the Vickers hardness ranges from 28.8 to 34.6 GPa, the flexure strength ranges from 233.3 to 523.4 MPa, and the fracture toughness ranges from 6.0 to 7.0 MPa m1/2, respectively. The thermal shock properties of B4C–ZrB2 ceramics were also investigated using water quenching method. The critical thermal shock temperature difference (ΔTc) for B4C–10 vol.% ZrB2, B4C–20 vol.% ZrB2, B4C–30 vol.% ZrB2 and B4C–40 vol.% 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–30 vol.% ZrB2 is found to exhibit the optimal thermal shock behavior.