(Hf,Zr,W,Mo,Ti)B2 High-Entropy Boride Ceramics Fabricated by Boro/Carbothermal Reduction Method Combined with SPS

In order to further improve the density and properties of high-entropy boride ceramics, (Hf,Zr,W,Mo,Ti)B₂ high-entropy boride ceramics were prepared by boro/carbothermal reduction combined with SPS. The phase composition, microstructure, and mechanical properties of the ceramics were studied, and the results showed that (Hf,Zr,W,Mo,Ti)B₂ high-entropy boride powder contained a highentropy phase, an oxides impurities phase, a WB phase, and a HfB₂ phase at 1600 °C. After sintering at 2000 °C, there was no oxide impurity in the (Hf,Zr,W,Mo,Ti)B₂ high-entropy boride ceramics, which consisted of a high-entropy phase and a small amount of WB second phase. The hardness and fracture toughness were 29.9 ± 1.0 GPa and 3.36 ± 0.21 MPa·m^1/2, respectively. The hardness was higher than the high-entropy boride ceramics with the same components prepared by in situ reactive sintering and borothermal reduction. The mechanical properties of the high-entropy ceramics obtained by boro/carbothermal reduction was excellent. and were higher than those reported in the literature of the same component.