A aluminum coating with chromium-free passivating film formed on AZ91D magnesium alloy

An aluminized layer with strong adhesion was formed on the surface of AZ91D magnesium alloy which was impregnated in chromium-free passivating agent zirconate for passivating treatment. The coatings on the samples were examined to analyze the anodic polarization behavior, the mechanism of corrosion resistance, and the brittleness. As a result, it shows that corrosion resistance of aluminized magnesium alloy compared to galvanized film has been greatly improved. Besides, when the initial corrosion began to appear in the coatings, the corrosion rate of aluminized film is much lower than that of galvanized film on magnesium alloy. In addition, since the low brittleness of aluminized layer on magnesium alloy, the plating does not produce crack after bending.