High-quality spherical zirconium alloy powders prepared by thermal plasma treatment for additive manufacturing

•Highly spherical zirconium alloy powders are prepared by plasma spheroidization.•Powders with a smooth and burr-free surface have average sphericity of over 95%.•The content of oxygen and hydrogen has decreased significantly after treatment.•Uniform and narrow particle distribution were achieved through spheroidization. Spherical zirconium alloy (Zr-4) powders produced by thermal plasma spheroidization show great potential for additive manufacturing in the nuclear industry. After plasma treatment, high-sphericity (>0.95) powders with a narrower distribution and lower impurity element contents have been obtained. The spheroidized powders with a uniform particle distribution of 40 ~ 80 μm have been determined and exhibits a dense structure with good surface finish. Meanwhile, no element segregation is detectable after quick solidification of the alloy powders. The XRD patterns indicate that residual hydride phases have been substantially removed after spheroidization, significantly improving their purity. Furthermore, the content of oxygen and hydrogen has been decreased by ~ 34.9% (from 0.43 wt.% to 0.28 wt.%) and ~ 88.0% (from 0.92 wt.% to 0.09 wt.%), respectively, compared to the raw alloy powders. The effective and scalable strategy for fabricating spherical zirconium alloy powders may potentially broaden the application of metal zirconium for additive manufacturing.