Investigation on local dissolution and anti-corrosion characteristic of directed energy deposition (DED) CoCrMo-xCu alloys in marine environment

Abstract

This study investigates the result of copper addition on the microstructure, local dissolution, and anti-corrosion characteristic of DED CoCrMo-xCu alloys. The regulation mechanism of copper content on alloy properties was revealed by using EIS, cyclic polarization, and the Mott-Schottky test, along with microstructure characterization techniques including SEM, EBSD, EPMA, SKPM, TEM, and XPS. The results reveal that the addition of Cu enhances grain refinement, promotes a denser passive film, and causes improved corrosion resistance of CoCrMo-2Cu. However, excessive Cu content can lead to microstructure segregation increases and the stability of passive film reduces, resulting in local dissolution and decreasing of corrosion resistance. This study provides valuable insights into optimizing Cu content for CoCrMo alloys to improve their performance in marine environments, offering potential applications in structural materials and anti-fouling surfaces.