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.