Anti-corrosion Performance of Organic-inorganic Duplex Coating on Magnesium Surface

Using γ-aminopropyltrimethoxysilane (γ-APS) as precursor, silane solution was prepared by sol-gel method, and then the organic-inorganic duplex protecting coating on Mg was prepared by Mg dipped into the silane solution. The surface morphology of the organic-inorganic hybrid coating was observed by metallographic microscopy. The results show that the organic-inorganic duplex protecting coating is smooth and more adhesive than the chromate film. Potentiodynamic polarization curve measurement and metallographic microscopy results show that the corrosion potential of the organic-inorganic duplex protecting coating is higher and corrosion current is smaller than those of the chromate film, and thus the coating possesses better anti-corrosion performance. The organic-inorganic duplex protecting coatings is environmentally friend. The suggested process can replace the chromate process effectively.