Investigation of anti-corrosion performance of ZIF-8/Zn(OH)F composite films on Zn–Al coating

This study investigates the corrosion resistance of ZIF-8/Zn(OH)F composite films with different molar ratios on Zn–Al coatings, emphasising the enhancement in their anti-corrosion properties. ZIF-8/Zn(OH)F composite films with molar ratios of 1:4, 1:8 and 1:16 were prepared using the ligand exchange method. Analysis through XRD, SEM and electrochemical corrosion tests revealed that the composite film with a 1:8 molar ratio exhibited the best corrosion resistance, enhancing the protection efficiency of the Zn–Al coating by over 94.6%. After 120 h of immersion in a 3.5 wt.% NaCl solution, the 1:8 molar ratio composite film exhibited a charge transfer resistance of 19,580 Ω.cm ² and the lowest corrosion current density of only 2.32 × 10 ⁻⁵ A/cm ² . The study results suggest that the 1:8 molar ratio ZIF-8/Zn(OH)F composite film not only effectively enhances the corrosion resistance of Zn–Al coatings but also offers new insights into the design of anti-corrosion materials.