A review on the plasma electrolytic oxidation (PEO) process applied to copper and brass

Copper and its alloys, with their unique characteristics including a low coefficient of thermal expansion, a high melting point, superior thermal and electrical conductivities, outstanding ductility, and commendable resistance to corrosion, are considered highly suitable for applications in power generation, electrical sectors, military operations, and heat exchange pipelines in submarines. Despite its many advantages, the application of copper is somewhat restricted due to its low strength, hardness, and limited resistance to corrosion and wear. However, the plasma electrolytic oxidation (PEO) process, which can generate multifunctional oxides such as CuO, Cu2O, and ZnO, offers a promising method for improving the wear and corrosion characteristics of copper-based materials. This paper presents an overview of the latest advancements in the PEO treatment applied to copper and brass. This review offers a comprehensive understanding of the formation of PEO coatings on copper and brass substrates. It explores how the PEO process, its parameters like electrolyte composition, nanoparticle addition, and various post-PEO treatment methods can influence the coatings' morphology, composition, and resistance to corrosion and wear. This review serves as a valuable guide for future research in the field of PEO treatment for copper and its alloys.