Mg-Al LDH conversion films grown on Mg alloys under micro-galvanic effects

Abstract

Mg-Al LDH conversion films were synthesized by the hydrothermal treatment in deionized water on various as-cast Mg-Al alloys. The micro-galvanic effect on the growth of the Mg-Al LDH films and their corrosion protection properties were investigated. It was found that a higher Al solute content in matrix phase reduced the micro-galvanic effect between the matrix phase and secondary phase. However, both phases could be partially dissolved to provide the necessary Al source for the growth of LDH films. A higher Al solute in the matrix phase was helpful to the formation of more protective LDH films.