High-Temperature and High-Pressure Synthesis of High-Entropy Transition Metal Diborides

High-entropy transition metal diborides have been extensively studied due to their high mechanical and thermodynamic properties. However, the conventional synthesis methods of these materials are inefficient. In this paper, we synthesized six types of high-entropy transition metal diborides based on VB₂, NbB₂, and TaB₂ by high-temperature and high-pressure solid-state reactions at 5.5 GPa and 2300 °C. The high pressure promoted the efficiency of solid-state reaction and facilitated the synthesis of high-entropy transition metal diborides. The X-ray diffraction and energy dispersive X-ray spectroscopy results have been confirmed that the six types of high-entropy transition metal diborides possessed pure phase compositions without oxide impurities or second phases, and exhibited uniform elemental distribution without elemental segregation. These results demonstrate that the synthesis of high-entropy transition metal diborides by using high-temperature and high-pressure solid-state reaction method is effectiveness and practicality.