In situ growth of Mg-Zn-Al LDHs by ZIF-8 carrying Zn source and micro-arc oxidation integrated coating for corrosion and protection of magnesium alloys

For realistic large-scale applications, it is essential to prepare effective anti-corrosion coatings. In this study, ZIF-8 was first grown in situ on the pre-prepared MAO coating. Then, the Zn source in ZIF-8 and Mg and Al in the MAO coating were used to form an integrated coating, and the Mg-Zn-Al LDHs coating was formed on the MAO coating in one step by hydrothermal method (Mg-Zn-Al/Z LDHs). X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to confirm the chemical states, structural composition, and morphology of the Mg-Zn-Al/Z LDHs coating. The potentiodynamic polarization revealed that the corrosion protection ability of Mg-Zn-Al/Z LDHs coating (1.48 x 10-8 A/cm2) in 3.5 wt% NaCl solution is stronger than MAO coating (3.17 x 10-6 A/cm2). The feasibility of boosting the anti-corrosion ability of MAO coating was established by thorough examination of potential corrosion protection mechanisms in relation to Mg-Zn-Al/Z LDHs coating.

Automated summary

Preparing effective anti-corrosion coatings is essential for realistic large-scale applications. In this study, ZIF-8 was grown in situ on a pre-prepared MAO coating, and an integrated coating was formed using the Zn source in ZIF-8 and the Mg and Al in the MAO coating. The Mg-Zn-Al/Z LDHs coating was successfully formed by hydrothermal method and exhibited stronger corrosion protection ability compared to the MAO coating.