Synthesis of ZIF-67@ZIF-8 with Core-shell Structure for Enhancing Epoxy Coating Corrosion Protection Property on Magnesium Alloy

Nanocontainers with corrosion inhibitors are an effective means to protect metals from corrosion. However, such coatings need to release the inhibitors rapidly to form an on-demand barrier on the metal surface, whereas coating damage needs to be minimized to prevent excessive leakage. Herein , this function is achieved by ZIF-67@ZIF-8 nanoparticles, a metal organic frame material with core-shell structure, by acting as a functional filler. The structure and composition of ZIF-67 and ZIF-67@ZIF-8 nanoparticles are assessed by TEM, SEM and XRD. The findings of UV spectroscopy and immersion experiments show that ZIF-67@ZIF-8 nanoparticles rapidly release 2-MI to the damaged area of the metal surface in acid conditions. In addition, in a neutral environment, only limited amounts of 2-MI (less than 4%) are released. The coating has high corrosion resistance after immersion for 120 h in acidic condition, as exhibited by EIS, and thus potential application value.