Characterization and Structure Analysis of the Anodic Film Formed on AZ31 Mg Alloy in KOH Alkaline Solution with Various Additives

AZ31B Mg alloy was anodized under the current density of 20 mA cm-2 for 3.6 ks in KOH alkaline solutions contains 0.60 M KF, 0.09 M Na 3 PO 4 .12H 2 O, 0.45 M Al (OH) 3 and 0.13 M KMnO 4 at 298 °C. Pores structure anodic film was formed on magnesium alloy surface; the pours structure was also observed in the lower part of the anodic film. The anodic film consisted of MgO and MgAl 2 O 4 . The anodized film showed higher pitting potential from anodic polarization measurement in 0.1 M NaCl solution compared to non-anodized magnesium alloy specimen and leads to improve the corrosion resistance of anodized AZ31 magnesium alloy.