Effect of Methanol on Plasma Electrolytic Oxidation Process of Mg Alloy

The effect of methanol on the discharge characteristic of plasma electrolytic oxidation(PEO) of magnesium alloy AZ31 was investigated by constant voltage mode in electrolyte containing KOH, Na2SiO3, methanol and water. The amount of dissolved magnesium ions in the electrolyte was measured by atomic absorption spectrophotometer. The results showed that methanol had remarkable effect on the discharge characteristic of PEO of magnesium alloy. As the concentration of methanol increased, the amount of dissolved magnesium ions decreased, and the dropping corrosion resistance and uniform corrosion resistance could be enhanced considerably. Methanol reduced the energy consumption of PEO process effectively. When the concentration of methanol in the solvent was 12%, the energy consumption reduced by 42.9% than that of free of methanol.