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.