Comparison of corrosion resistance of MgAl-LDH and ZnAl-LDH films intercalated with organic anions ASP on AZ31 Mg alloys

Abstract

Abstract The aspartic acid (ASP), an environment-friendly corrosion inhibitor, was explored to intercalate into the ZnAl-layered double hydroxide (ZnAl-LDH) and MgAl-LDH coatings on AZ31 magnesium alloys by a facile one-step hydrothermal method. The morphology, composition, structure and corrosion resistance of the prepared coatings were comparatively investigated. It is found that the uniform and dense layered nanosheet (NS) vertically grows on the substrate, and the MgAl−ASP-LDH films exhibit a three-dimensional (3D) rose-like sheet structure with high ratio of pore coverage. The MgAl−ASP-LDH coating exhibits better corrosion resistance and durability of longtime immersion than ZnAl−ASP-LDH coating. The corrosion current density of two coatings is two or three orders of magnitude lower than that of bare Mg alloy, indicating that ZnAl/MgAl-LDH films intercalated with organic ASP anions can significantly improve the corrosion resistance of Mg alloy.