For identifying the relative corrosion resistance among the hot-dip pure Zn sheet, Zn-Fe sheet and Zn-Al-Mg sheet，and providing data support to switch to Zn-Al-Mg steel sheet, scanning electron microscope(SEM)was utilized to observe the section micro morphology and surface microstructure characteristics after phosphating of the three kinds of coatings.Meanwhile, the weight loss and average corrosion rate of different types of coated steel and the same type of coated steel with different coating weights after experiment were compared via neutral salt spray test.Results showed that The corrosion resistance of Zn-Fe alloy plate after phosphating was equivalent to that of pure zinc plate, and Zn-Al-Mg plate had the best corrosion resistance, and the relative corrosion resistance was about 6.5 times that of the pure zinc plate and Zn-Fe alloy plate.Compared with 50 g/m2 pure zinc plate and Zn-Fe alloy plate, the Zn-Al-Mg plate with 35 g/m2 coating weight had higher corrosion resistance.
