Effect of Two Alloying Elements on the Microstructure and Properties of Zn–3Al–2Mg Alloy

In order to obtain multicomponent alloy coating with high corrosion resistance, the effects of two alloying elements (Zr and Ni, Ti and Ni, Ti and Zr) on the microstructure and properties of Zn–3Al–2Mg alloy have been investigated. The results from XRD and SEM analysis indicate the formation of phases such as Al2Zr, Al2Ni, Al2Ti, and Al2(Ti,Zr), along with a refinement of the grains after adding two of the three alloying elements (Zr, Ti, and Ni). The hardness of the alloys is the highest when 0.1 wt % of both Zr and Ni are included. Additionally, incorporating these alloying elements increases the corrosion potential and reduces the corrosion current density of the alloys. Furthermore, when Ti and Zr are added, the formation of loose, porous ZnO is inhibited, while the creation of ZnAl2O4 and Zn5(CO3)2(OH)6—both having a dense structure and good adhesion—is promoted, leading to improved corrosion resistance of the alloy. Due to the excellent self-healing ability in the corrosion process, Zn–3Al–2Mg–0.1(TiZr) alloy has wide application prospects in hot-dip galvanized coating applications, especially in the corrosion resistance of steels.