Additively manufactured (AM) Cu-Ni alloys are being explored for applications requiring high corrosion and wear resistance. However, the corrosion performance of AM Cu-30Ni, particularly in the as-printed versus polished conditions, remains insufficiently understood. In this work, the microstructure and corrosion behavior of LPBF-fabricated Cu-30Ni alloy were systematically investigated and benchmarked against conventionally cast Cu-30Ni. Microstructural characterization revealed LPBF-specific features, including overlapping melt pools, fine-scale cellular structure, and minor Mn-Fe-Si-O inclusions. Potentiodynamic polarization in 3.5 wt.% NaCl showed that the as-printed AM alloy exhibited no obvious passive region, but with a significantly more noble corrosion potential than the cast material. After removing as printed layer by grinding and polishing, both cast and AM alloys demonstrated passive-like behavior, with the AM alloy exhibiting slightly higher breakdown potential. Long-term immersion testing (1 week, 1 month, and 6 months) indicated that AM Cu-30Ni developed a more compact and adherent corrosion layer than the cast alloy, which formed a porous and heterogeneous film. Overall, the results demonstrate that AM Cu-30Ni meets or exceeds the corrosion performance of cast Cu-30Ni and offers promising potential for engineering applications.
