Corrosion and Electrochemical Evaluation of Coated Magnesium Alloys

The electrochemical corrosion performance of E-coated, which is also known as electro-coated or electrophoresis-coated (a process of using direct current to deposit an organic coating), and powder-coated magnesium alloys AZ31 and AZ61 was investigated using AC/DC/AC (alternating current/directcurrent/alternating current), electrochemical impedance spectroscopy (EIS), salt spray, hydrogen evolution, and scanning electron microscopy (SEM). The AC/DC/AC technique was proven to be a rapid corrosion performance evaluation technique for coated Mg alloys. Results also suggest that the coating thickness, porosity, and corrosion resistance of the substrate Mg alloy can influence the corrosion protection performance of a coating on a Mg alloy.