Effects of Adding Potassium Permanganate into the Electrolyte on the Properties of Microarc Oxidation Coating Developed on Pure Copper

This study explores the effect of potassium permanganate (KMnO₄) concentration on the microarc oxidation (MAO) coatings of high-purity copper. Results show that the KMnO₄ addition reduces overall porosity but enlarges individual pores. The resulting manganese oxides increase coating thickness, hardness, roughness, and impart transient hydrophobicity. Tribological tests confirm improved wear resistance under high loads. Although larger pores slightly reduce corrosion resistance, the coating still protects the substrate. Additionally, the coating growth mechanism is clarified, providing a basis for optimizing MAO coatings on pure copper through secondary processing.