Study of the corrosion behavior and mechanism of a hot-dipping Zn–6Al–3Mg alloy coating in 3.5 wt% neutral NaCl solution

In this study, the microstructure of a hot-dipping Zn–6Al–3Mg alloy coating was characterized and its histomorphological, electrochemical and corrosion products changes when submerged in a 3.5 wt% NaCl solution were investigated. Further, the effects of different microstructures on the corrosion resistance of the coating and the corrosion mechanism were investigated. Different microstructures lead to significant differences in the corrosion resistance of the coating, indicating the different roles microstructures play in this process. The ternary eutectic phase was preferentially corroded, where corrosion products were formed preferentially and gradually covered the coating surface. This prevented the corrosive medium from further attacking the coating, improving its corrosion resistance.