Enhancement of corrosion resistance and antibacterial properties of PEO coated AZ91D Mg alloy by copper- and phosphate-based sealing treatment

Preparing dense coatings with both good corrosion resistance and antibacterial properties on the Mg alloys surfaces using conventional surface treatment methods is difficult. In this study, we used a solution containing Cu2+ and phosphate to seal a plasma electrolytic oxidation (PEO) coated AZ91D Mg alloy. After the treatment, a formed dense deposition layer significantly improved the corrosion resistance of the PEO-coated alloy. At the same time, the release of Cu2+ conferred excellent antibacterial properties on the Mg surface. The chemical and physical models for the sealing reaction and corrosion processes were established, providing a theoretical basis for future studies.