Effects of electric parameters on corrosion resistance of
anodic coatings formed on magnesium alloys
(1. Jiangxi Key Laboratory of Surface Engineering, Jiangxi Science and Technology Normal University,
Nanchang 330013, China;
2. School of Materials Science and Engineering, Jiangxi Science and Technology Normal University,
Nanchang 330013, China;
3. School of Electronics, Jiangxi University of Finance and Economics, Nanchang 330013, China)
Nanchang 330013, China;
2. School of Materials Science and Engineering, Jiangxi Science and Technology Normal University,
Nanchang 330013, China;
3. School of Electronics, Jiangxi University of Finance and Economics, Nanchang 330013, China)
Abstract: Anodic coatings were obtained by micro-arc oxidation on AZ91HP magnesium alloys in a solution containing 10 g/L NaOH and 8 g/L phytic acid. The effects of electric parameters including frequency, final voltage, duty cycle and current density on the corrosion resistance of anodic coatings formed on the magnesium alloys were investigated by using an orthogonal experiment of four factors with three levels. The results show that the final voltage plays a main role on the coating properties. The orders of affecting corrosion resistance and coating thickness are separately ranked from high to low as, final voltage>duty cycle>current density>frequency and final voltage>current density>frequency>duty cycle. The final voltage influences the corrosion resistance of the anodized samples mainly by changing the surface morphology and coating thickness.
Key words: magnesium alloys; micro-arc oxidation; electric parameters; corrosion resistance