Study of the corrosion resistance of MB8 Mg alloys by micro-arc oxidation

With scanning electron microscopy(SEM),potentiodynamism polarization curves,electronmicroscopy impedance spectroscopy(EIS),corrosion resistance of ceramic coating produced on MB8 magnesium alloy substrates by micro-arc oxidation(MAO) technique had been investigated.The results show that a great deal of comparatively uniform discharge micro-pore whose diameters are 1～3μm are distributed in the surface of film;the oxide coating contains transition layer,compact layer and porous layer,the compactness thickness amounts to 60%,about 6～7μm.Potentiodynamism polarization curves and electrochemical impedance test demonstrate that micro-arc oxidization improves the corrosion resistance of Mg alloys greatly.