Changes in Powder Surface Chemistry during Reuse of Pure Copper in Powder Bed Fusion - Electron Beam

Powder degradation during additive manufacturing poses a significant challenge to achieving optimal part quality and maximal powder feedstock utilization and hence sustainability of the process. Pure copper possesses high optical reflectivity and excellent thermal and electrical conductivity. Powder bed fusion - electron beam (PBF-EB) is a promising method for fabricating pure copper parts as it can melt materials regardless of their reflectivity and operates under vacuum preventing oxidation. This study investigates the influence of pure copper powder properties and reuse on the powder surface oxide chemistry and processability by PBF-EB. Changes in powder surface chemistry were studied by HRSEM and X-ray Photoelectron Spectroscopy in virgin and reused state. Results indicate that there is evident degradation in powder properties during reuse with increase in oxygen content, connected to increase in surface oxide layer as well as transformation of CuO into Cu2O and formation of Cu(OH)2 on top surface during handling.