Corrosion of molybdate intercalated hydrotalcite coating on AZ31 Mg alloy

Abstract

A molybdate intercalated hydrotalcite (HT-MoO₄²⁻) coating with a nanosized lamellar structure was synthesized on AZ31 Mg alloy by a combination of the co-precipitation and hydrothermal processes. The characteristics of the coatings were investigated by SEM, EPMA, XRD, EDS and FT-IR. The corrosion resistance of the coatings was assessed by potentiodynamic polarization, electrochemical impedance spectrum, and hydrogen evolution. The results indicated that the HT-MoO₄²⁻ coating, characterized by interlocking plate-like nanostructures, ion-exchange and self-healing ability, has a potential to be a “smart” coating capable of responding to stimuli from the environment.