Work

Surface stability and electrochemical behavior of additively manufactured copper in repository-relevant environments

Year: 2026

Type: article

Abstract: The long-term stability of disposal canisters is determined by their corrosion resistance in deep geological disposal environments. This study investigates the surface stability, electrochemical behavior, and mechanical properties of wire arc additively manufactured (WAAM) Cu and Cu alloys compared to forged oxygen-free copper (OFC) in repository-relevant groundwater. Electrochemical and surface characterizations in aerobic and anaerobic groundwater conditions were correlated with nanoindentation results. Under aerobic conditions, all materials exhibited comparable corrosion behavior with predominantly uniform corrosion. In contrast, under anaerobic conditions, AM-Cu showed higher corrosion current densities than OFC, associated with heterogeneous surface reactions. In sulfide-containing environment, the corrosion current density of OFC was approximately 3.5 times lower than AM-Cu, despite the formation of a denser Cu2S layer on AM-Cu. Tafel analysis further revealed a gradual increase of current density in anodic region, indicating instability of the CuCl- derived surface film compared to the stable response of OFC. Nanoindentation results showed that AM-Cu possesses higher hardness and elastic modulus than OFC, indicating a trade-off between mechanical strengthening and electrochemical stability. These findings demonstrate that process-induced heterogeneity in AM-Cu governs corrosion film evolution and electrochemical behavior under repository-relevant environments.

Source: Applied Surface Science

DOI: 10.1016/j.apsusc.2026.167855