Enhancing AZ31 magnesium alloy with self-healing plasma electrolytic oxidation coatings incorporated with Cu-MBT-HNTs nanocomposite

Plasma electrolytic oxidation (PEO) coatings with long-lasting active protection were prepared by incorporating 2-mercaptobenzothiazole (MBT)-loaded halloysite nanotubes (HNTs), followed by introduced insoluble Cu-MBT complex, has been achieved in present study. To further compare and analyze the corrosion characteristics of the sample, different halloysite nanotubes (HNTs, MBT@HNTs) profiles were also added to the electrolytes for the preparation of different oxide films (HNTs-PEO and MBT-HNTs-PEO). The coatings were characterized by scanning electron microscopy (SEM), film thickness meter, roughness meter, energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The corrosion behavior was evaluated by electrochemical impedance spectroscopy (EIS), and open circuit potential (OCP) tests. The results show that the long-term corrosion resistance of magnesium alloys can be improved by adding Cu - MBT-HNTs owning to the self-healing effect.