Study on the Properties of Micro - arc Oxidation Self - assembled Composite coatings on Magnesium Alloy

The micro-arc oxidation / bis[(γ-triethoxysilyl)propyl]tetrasulfide (BTESPT) self-assembled composite coatings were prepared on the surface of magnesium alloy by self-assembly (SAM) and micro-arc oxidation (MAO). The surface morphology and composition of the composite coatings were characterized by scanning electron microscopy (SEM) and energy dispersion spectrometry (EDS). The corrosion resistance of the composite coatings was studied by electrochemical impedance spectroscopy (EIS), polarization curves and the experiments of immersion. The test results showed the anti- corrosion of the composite coatings were significantly improved compared with the pure micro-arc oxidation film. The formation mechanism of the self-assembled membrane on the micro-arc oxidation layer of magnesium alloy was investigated by dynamic simulation. The results showed that the self- assembled molecules were chemically adsorbed on the solid surface.