Growth behavior and corrosion resistance of graphene oxide/MgAl Layered double hydroxide coating grown on micro-arc oxidation film of magnesium alloys

The MgAl Layered double hydroxides (LDHs)/graphene oxide (GO) composite film was fabricated in situ on the micro-arc oxidation (MAO) film (MAO/LG) of AZ31 magnesium alloy in one step by hydrothermal chemical conversion method. The growth behavior and corrosion properties of LG films were investigated. The results show that the chemical structure, composition and morphology of the LG film will gradually change with the extension of the hydrothermal treatment time based on using the self-dissolved cation (Mg 2+ and Al 3+ ) in the MAO film as the source of growing LDHs without introducing any external metal cations. The potentiodynamic polarization showed that the MAO/LG-12 h coating (1.28 × 10 −9 A/cm 2 ) after in situ growth for 12 h was more corrosion resistant than the MAO coating (8.49 × 10 −6 A/cm 2 ). The synergistic effect of GO and LDHs can significantly improve the corrosion protection ability of MAO coating. In addition, the transition process of the growth behavior of the LG film layer on the MAO coating is explained in detail.