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 µm) 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 coef - ficient close to 0.9. The powder microstructure is characterized by the absence of internal pores, which are typi - cally 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, plasma-arc 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.