Plasma spheroidisation of high melt point materials on example of tungsten

Abstract

Particle shape and size, density and distribution are important characteristics of the powders processed by additive manufacturing processes e.g. Selective Laser Melting (SLM) or Electron Beam Melting (EBM). Spherical shape of powder particles allows to stably carrying out the process and affects also the manufactured objects properties. Desired morphology of the powder can be achieved by powder manufacturing process or by additional treatment of the non-spherical powders. This paper is dedicated to study spheroidization of tungsten powder by Atmosphere Plasma Spraying (APS). Influence of APS process parameters and preliminary powder treatment has been analysed. Scanning electron microscopy (SEM) was used for the evaluation of shape, size and distribution of post-processed powder particles.

Understanding powder degradation in metal additive manufacturing to allow the upcycling of recycled powders

“…It was believed that tweaking the parameters used in plasma spheroidisation caused these changes. This was confirmed by Kobiela et al (2015), finding that both the quality of the feedstock material and process conditions heavily influenced the output of the spheroidised material. Despite allegedly optimising the process, small cracks and pores were seen on the surface of spheroidised tungsten powder.…”

Plasma spheroidisation and characterisation of commercial titanium grade 5 powder for use in metal additive manufacturing

“…This may be attributed to the increase in available heat required for a given feed rate and particle size distribution to melt the powder particles resulting in sufficient surface melting and subsequent spheroidisation [15]. However, excessive plasma power (intensity) can result in over melting and vaporisation of finer powders resulting in significant mass loss, which is not desirable [16]. Narrow particle size distribution of raw materials can help to contain this problem [8].…”