Synthesis of single‐phase high‐entropy diboride powders and their spheroidization process

Abstract Spherical (Zr _.2 Ti _.2 Ta _.2 Nb _.2 Mo _.2 )B ₂ powders with a uniform particle size distribution are successfully prepared using a novel industrial approach, which combines spray‐drying process and thermal plasma sintering technology together. In this, single‐phase (Zr _.2 Ti _.2 Ta _.2 Nb _.2 Mo _.2 )B ₂ powders are first synthesized via a borothermal reduction process using a mixture of individual metallic oxides and boron powders as starting materials. The influence of boron powder content on the structure of prepared powders is researched. Then, (Zr _.2 Ti _.2 Ta _.2 Nb _.2 Mo _.2 )B ₂ granules are prepared after wet‐grinding and spray‐drying process, which exhibit a spherical shape and homogeneous element distribution. RF induction thermal plasma is finally used to sinter the granulated particle, and the apparent density of sintered spherical powders is increased to 2.57 g/cm ³ from 1.43 g/cm ³ . Such powders are in potential demand for additive manufacturing techniques, and the successful synthesis of spherical (Zr _.2 Ti _.2 Ta _.2 Nb _.2 Mo _.2 )B ₂ powders may guide the way toward the preparation of many other spherical high‐entropy diboride powders.