Synergistic effect of graphene oxide/ ternary Mg-Al-La layered double hydroxide for dual self-healing corrosion protection of micro-arc oxide coating of magnesium alloy

Abstract

Micro-arc oxidation (MAO) coatings have good corrosion protection properties and can effectively inhibit the corrosion of magnesium alloy surfaces in salt environments. This study aimed to achieve and improve the dual self-healing and corrosion resistance of MAO coating by in-situ growth to form a hybrid coating of vanadate (V2O74-) intercalated a graphene oxide (GO)-doped ternary Mg-Al-La layered double hydroxides (LDHs) (ternary L/G-V coating). The corrosion resistance and self-healing properties were verified by electrochemical experiments and scratch tests. Due to the synergistic effect of the strong barrier properties of GO and LDHs, the ternary L/G-V coating exhibits excellent anticorrosion ability. Interestingly, the ternary L/G-V coating also exhibits self-healing properties when corrosion ions reach the metal/coating interface due to the release of interlayer anionic corrosion inhibitor (vanadate) and rare earth cationic corrosion inhibitor (lanthanum) of LDHs. It makes up for coating defects in time and realizes the dual self-healing function of corrosion protection of MAO coating.