One-step synthesis of coral-like high-entropy metal carbide powders

Abstract

The synthesis of high-entropy metal carbide powders is critical for implementing their extensive applications. However, the one-step synthesis of high-entropy metal carbide powders is rarely studied. Herein, the synthesis possibility of high-entropy metal carbide powders, namely (Zr0.25Ta0.25Nb0.25Ti0.25)C (ZTNTC), via one-step carbothermal reduction was first investigated theoretically by analyzing chemical thermodynamics and lattice size difference based on the first-principle calculations, and then the ZTNTC powders with particle size of 0.5-2 μm were successfully synthesized experimentally. The as-synthesized powders not only had a single rock-salt crystal structure of metal carbides, but also possessed high-compositional uniformity from nanoscale to microscale. More interestingly, they exhibited the distinguished coral-like morphology with the hexagonal step surface, whose growth was governed by a classical screw dislocation growth mechanism.