Optimization of Environmentally Friendly Anodic Oxide Film for Magnesium Alloys

The magnesium anodizing treatment described in this paper is an environmentally friendly treatment which excludes the use of chromates, fluorine compounds, and phosphates. An alkali bath, which mimics conditions necessary to form naturally occurring magnesium salts, was selected as an electrolytic bath. The components of the electrolytic bath were optimized, and the samples were evaluated by salt spray test. The results suggest that the anodizing treatment with the optimized conditions on the surface of magnesium alloys AZ91 can achieve a higher level of corrosion resistance than the traditional chemical conversion and anodizing treatments which use chromates, fluorine compounds, and phosphates.