Production of spherical Inconel 625 powder for additive manufacturing by plasma-arc wire atomization: Influence of non-transferred and transferred arc modes on fine powder yield

The possibility of producing spherical powder from Inconel 625 nickel-based superalloy using plasma-arc wire atomization technology in both non-transferred and transferred arc modes has been experimentally confirmed.Particle size distribution analysis showed that using the non-transferred arc mode reduces the average powder diameter by 23% compared to the transferred arc mode and increases the yield of the fine fraction (below 63 m) from 40 to 62 wt.%.This increase in powder dispersity is achieved by using a reverse-polarity plasma torch with a hollow copper electrode and a divergent plasma-forming nozzle, which enables the formation of a high-velocity plasma jet.Morphological analysis showed that the powder has a regular spherical shape, with a sphericity coefficient close to 0.9.The powder microstructure is characterized by the absence of internal pores, which are typically found in gas atomized powders.Chemical composition analysis using energy-dispersive X-ray spectroscopy confirmed full compliance of the powder with the original feedstock wire material.Based on these results, plasmaarc wire atomization is recommended as an effective method for producing spherical Inconel 625 powder, fully meeting the requirements for fine powders in additive manufacturing applications.