Study on the anodizing of AZ31 magnesium alloys in alkaline borate solutions

A kind of environmentally friendly anodizing route for magnesium alloys, based on a new kind of organic additive (AA) contained traditional alkaline borate solution and 50 Hz civil ac current, has been studied. It is found that the formation of the anodic films is always coupled with the additive depended sparking and oxygen evolution, and the optimized ivory-white smooth anodic film possesses high corrosion resistance and excellent binding strength to AZ31 substrate. Meanwhile, The results also show that the structure, the corrosion resistance and the morphology of the anodic films are mainly dependent on the anodizing voltage, time and additives.