An Excellent Corrosion-Resistant Al-Si-Mg-Mn Hot-Dip Coating for Steel

The coating characterization and property assessment of hot-dip Al-Si-Mg-Mn alloy-coated steel are described in this work. To assess the coating’s morphology, composition, phase, and elemental depth profile, respectively, SEM, EDS, XRD, and GDOES sputtering were used. The results of the cross-sectional study showed that the coating consists mostly of two layers. Dendritic primary α-Al, Mg₂Si and Si segregation make up the thick outer layer. The thin inner layer of Al-Fe-Si intermetallic was identified as Al₈Fe₂Si phase. Compared to galvanized (GI) or traditional aluminized coatings on steel, potentiodynamic polarization tests indicated greater corrosion resistance due to lower corrosion current and higher negative corrosion potential. Further study in salt spray test exhibited excellent corrosion resistance with > 1400 h salt spray life.