A quasi-passivated film formed on as-solutionized Mg-Sm-Zn-Zr alloy in NaCl solution

Benefiting from a quasi-passivated film, as-solutionized Mg-Sm-Zn-Zr alloy exhibits an extraordinary corrosion resistance over currently reported Mg alloys. The breakdown potential and corrosion current density are respectively-1.208 VSCE and 3.9 mu A/cm(2) after 24 h immersion in 0.6 M NaCl solution. The film consists of an outer layer, an intermediate layer and a Zn-rich layer. The oxide of solute element Sm strengthens the intermediate layer, which plays the primary role of impeding corrosion, by filling the vacancies left by the selective dissolution of Mg. An approximate linearity exists between the film resistance and the thickness of the intermediate layer.

Automated summary

As-solutionized Mg-Sm-Zn-Zr alloy, benefiting from a quasi-passivated film, exhibits extraordinary corrosion resistance. The film consists of an outer layer, an intermediate layer, and a Zn-rich layer, and the oxide of solute element Sm strengthens the intermediate layer to impede corrosion.