Influence of Annealing Time on Microstructure and Corrosion Resistance of Zinc-Magnesium Alloy Coating

A combined process of depositing Mg by PVD (Physical Vapor Deposition) followed by annealing was used to acquire Zn-Mg alloy coating.Phase composition and microstructure of Zn-Mg alloy coating were analyzed by XRD,SEM and EDS.NSST (Neutral Salt Spray Test),NCCT (Neutral Cyclic Corrosion Test) and electrochemical test were conducted to investigate the corrosion resistance of Zn-Mg alloy coatings.Experiments showed that compared with GI (Galvanized Iron),although the apparent thickness increased within 10%,the corrosion resistance of Zn-Mg alloy coating was greatly enhanced.Besides,Zn-Mg alloy coating has excellent self-healing ability at the cut-edge and damaged areas.Zn-Mg alloy phases and corrosion products could account for the enhanced corrosion resistance of Zn-Mg alloy coatings.