Unveiling the inhibition mechanism of an effective inhibitor for AZ91 Mg alloy

The inhibition mechanism of a high-efficiency corrosion inhibitor (sodium dodecyl sulfate, SDS) is unveiled and the strategy to design effective inhibitors for Mg alloys is suggested. It was found that SDS is chemically absorbed on the cathodic intermetallics to inhibit micro-galvanic corrosion. Anodic Mg dissolution is also kinetically suppressed by physisorption of SDS since the long hydrophobic tail of the surfactant contributes to building up a protective corrosion layer. Utilization and synthesis of such green inhibitors can pave the way for a wider range of applications for Mg alloy and provide active corrosion protection for coated Mg surfaces.