Spheroidisation of tungsten powder by radio frequency plasma for selective laser melting

The growing interest in additive manufacturing of refractory metals is accompanied by the demand on spherical refractory meal powders with good flowability. In this work, the particle size distribution, particle morphology, phase and extent of oxidation of the tungsten powders spheroidised by radio frequency (RF) plasma with different feeding rates were investigated using scanning electron microscopy, laser particle size analysis and X-ray diffraction. It was demonstrated that spherical tungsten powders with extremely fine flowability and high apparent density were obtained by the RF plasma spheroidisation technology. High-density tungsten samples with negligible defects were prepared with the spheroidised powders by selective laser melting. The results would help pave the way for solving the problems in customising refractory metal parts by additive manufacturing.