Preparation and Anti-corrosion Performance of Chromium-free Zinc-aluminum Alloy Coating

In order to prepare chromium-free zinc-aluminum coating with good appearance and excellent corrosion resistance, alloy powders were used to replace mixed metal powders, epoxy silane AC-66 combined with sodium molybdate were used to replace chromate, and 4-level 5-factor orthogonal tests were designed, and the optimal formula was finally determined by investigating the corrosion resistance, adhesion strength, microstructure and morphology. XRD and SEM were applied to test and analyze the morphology and ingredients of the coating, the glossiness was observed intuitively, the salt fog resistance of the coating was tested by salt spray test and the corrosion resistance of the substrate and Al20 coating was tested by the electrochemical test. The results showed that the Al20 coating with optimal formula had the silver gray metallic luster and exhibited excellent corrosion resistance.