(Zr,Ti)B2 ceramics with enhanced hardness and fracture toughness were prepared by spark plasma sintering using platelet TiB2 and irregular ZrB2 as starting powders. The effects of sintering temperature (1700–1900 °C) and platelet TiB2 content (0–30 wt.%) on the sinterability, phase composition, microstructure, and mechanical properties of the (Zr,Ti)B2 ceramics were investigated. With increasing sintering temperature, the relative density of the solid solution increased from 89.9 ± 0.5% at 1700 °C to 97.7 ± 0.4% at 1800 °C, followed by no significant change upon further temperature elevation; however, the relative density showed an initial increase and subsequent decrease with increasing TiB2 content. Under optimized parameters (1800 °C, 3 min, 50 MPa, with a TiB2 content of 30 wt.%), (Zr,Ti)B2 ceramics achieve a maximum hardness of 24.9 ± 1.0 GPa, a fracture toughness of 5.0 ± 0.3 MPa·m1/2, and a relative density of 96.5 ± 0.5%. The high content of platelet TiB2 refined the (Zr,Ti)B2 grain size, reducing the D50 by 25.8% to 1.70 μm compared to the 20 wt.% content. This study provides a novel perspective for the design and preparation of high-performance ceramics.
Song et al. (Sat,) studied this question.