Electrochemical Analysis of Corrosion Resistance of Micro-arc Oxidized Die-casting Magnesium Alloy AM60

The effect of the surface state of micro-arc oxidation (MAO) films on corrosion resistance of die-casting AM60 Magnesium alloys in 3.5% NaCl solution was investigated by means of polarization curve measured with IM6e electrochemistry workstation.The thickness of MAO films samples was 10 μm,20 μm and 30 μm respectively.The Tafel slopes were analyzed.The results showed that the Icorr was decreased by a factor of 100 to 10000 times due to MAO treatment.The Icorr of samples decreased with the increase of thickness of the films,when the surface of samples was not polished.A lower Icorr could be obtained when the thickness of the films was 30 μm.The Icorr of oxide films could be decreased further more by surface polishing,and the lowest Icorr could be obtained when the thickness of the films was 20 μm.