Environmental impact of powder production for additive manufacturing: Carbon footprint and cumulative energy demand of gas atomization

Abstract

The production of metal powder required for certain metal additive manufacturing processes has a significant environmental impact on the process chain. In particular, there is a lack of energy- and resource-related data on the environmental impact of industrial powder production and in-depth analysis of individual process steps. This study aims to provide a reliable life cycle inventory and, based on this, to determine the global warming potential (GWP) and cumulative energy demand (CED) resulting from the industrial production of melt atomized metal powders for additive manufacturing using gas atomization within the framework of a life cycle assessment (LCA). In this LCA, considering an average electricity mix at a production site in Germany, the GWP for closed-coupled atomization ranged from 4.61 kg CO₂-eq./kg to 16.71 kg CO₂-eq./kg. The results are slightly lower than those of free-fall atomization with a GWP between 5.58 kg CO₂-eq./kg and 24.81 kg CO₂-eq./kg. The need for inert gas is a major contributor to the environmental impact. If argon is used as an atomizing gas instead of nitrogen, the environmental impact increases, since argon has a GWP and CED approximately six times higher than nitrogen. Preheating the inert gas reduces the requirement and thus also the resulting environmental impact. This study provides a crucial basis for assessing the environmental impact of powder metal additive manufacturing processes and, enabling environmentally friendly process and product design. In addition, effective strategies to reduce the environmental impact of gas atomization can be identified based.