Abstract: AM60B magnesium alloy was treated by means of micro-arc oxidation (MAO) in silicate system. The corrosion behavior of the film coated in 3.5 % NaCl medium was studied by using cyclic voltammetry (CV), Tafel polarization curve and electrochemical impedance spectroscopy (EIS). The result showed that the corrosion resistance of the film on AM60B magnesium alloy would be significantly improved after MAO treatment. Compared with the film coated under low voltage, the micro-pore size in the film coated under high voltage would be slightly larger, but the number of micropores would significantly reduce, and the thickness of the film would obviously increase, so that making the film exhibit extremely strong resistance and excellent corrosion resistance in entire corrosion process. Even at the end of the test, the corrosive medium would still not penetrate the coating into the interface between the film and the substrate. Nevertheless, when the film was coated under low voltage, the corrosive medium would already penetrate the film to erode the substrate.

Key words: AM60B magnesium alloy, micro-arc oxidation, corrosion behavior