Spheroidization of tantalum powder by radio frequency inductively coupled plasma processing

Abstract

In this work, we used radio frequency (RF) plasma spheroidization to transform irregularly shaped tantalum powders to spherical ones. After RF plasma treatment, the majority of particles were spheroidized with the presence of a small number of irregular particles. The mean particle size becomes finer and the particle size distribution narrower, as compared with the starting powder. A few non-spherical or even irregular tantalum powders still existed. Although argon gas was used in the plasma chamber, oxygen contamination still occurred. A thin layer of oxide film was found on the surface of particles, while the particle interiors were inferred free of oxygen. The powder characteristics had been significantly improved. After spheroidization treatment, the apparent density, tap density and powder flowability significantly increased from 7.03 g/cm3 to 8.9 g/cm3, 8.6 g/cm3 to 10.05 g/cm3, and 12.41 s/(50 g) to 7.96 s/(50 g), respectively, in comparison with that of raw powders. This study presents a feasible method for fabricating spherical tantalum powders, which may potentially broaden the application for metal additive manufacturing.