Chloride ion-responsive active protection epoxy composite coatings realized by 2-Mercaptobenzimidazole and 2-Mercaptobenzothiazole intercalated Mg-Al layered double hydroxides

Designing functionalized anti-corrosion fillers for harsh corrosive environments remains a significant challenge in the field of coatings. In this study, corrosion inhibitors 2-Mercaptobenzimidazole (MBI) or 2-Mercaptobenzothiazole (MBT) were intercalated into Mg-Al layered double hydroxides (LDH) using the calcination-rehydration method. For both inhibitors, with the addition of 3 wt% intercalated LDHs, the composite epoxy (EP) coatings exhibited favorable overall properties and anti-corrosion capabilities. The electrochemical impedance spectroscopy (EIS) and localized electrochemical impedance spectroscopy (LEIS) were used to investigate the scratched pure EP, LDH-MBI/EP, and LDH-MBT/EP coatings. The results showed that LDH-MBI/EP and LDH-MBT/EP demonstrated significant ion-responsive behavior and active protection capabilities.