The characterization of plasma electrolytic oxidation coatings on AZ41 magnesium alloy

Plasma Electrolytic Oxidation (PEO) was carried out on AZ41 magnesium alloy. The interrelation between the silicate-alkaline electrolyte composition and the maximum duration of defect-free PEO modifying, thickness, through porosity, and electrochemical response of the formed coatings were studied. Effects of the two-stage PEO treatment and additives of KF, NaF, and ZrO2 nanoparticles in composition of silicate-alkaline electrolyte on the coatings characteristics were also investigated. Results show that the two-stage PEO treatment and the additions of 5 g/l KF and 2 g/l ZrO2 nanoparticles all have positive effect on decreasing of corrosion current density of PEO coated alloy. For the untreated AZ41 alloy, the corrosion current density was 8.00 ∙ 10− 1 A/m2. After PEO treatment, the minimum corrosion current density value of 1.0·10− 4 A/m2 was obtained.