Abstract:In order to improve the property of traditional Ce-based conversion coatings, Ce-silane-ZrO₂ composite coatings were successfully prepared on 1060 aluminum. The microstructure, chemical element composition and corrosion resistance of Ce-based conversion coatings and Ce-silane-ZrO₂ composite coatings were investigated by SEM, AFM, XPS and EIS analyses. Stacking structure of the composite coating can be observed. The inner layer of the composite coatings mainly consists of oxide and hydroxide of Ce(III), and the silane network is composed of the outer layer together with a small amount of Ce(IV) hydroxide. By adding silane and ZrO₂ nanoparticles into Ce-based conversion coatings, the porosity and the micro cracks of the coatings decrease apparently accompanying with the improvement of the corrosion resistance.

Key words: aluminum; conversion coatings; corrosion resistance; surface morphology; chemical composition