Effect of Type and Concentration of Aqueous Solutions on Corrosion Behaviour of Plasma Electrolytic Oxide Films on ZM21 Mg Alloy

Plasma electrolytic oxidation (PEO) is a technique employed to significantly enhance the corrosion and tribological properties of the materials by forming an oxide ceramic film on the surface of the material. In this investigation, ZM21 Mg alloy was subjected to PEO treatment in silicate and phosphate-based aqueous solutions of 5grams and 10 grams per liter concentrations. The oxide film was characterized using SEM, profilometer, thickness meter, and polarization test. Results showed that the oxide film obtained with 10g/L phosphate-based solution offers higher corrosion resistance than the oxide films formed with other solutions.