Benzoate Intercalated Mg-Al-layered Double Hydroxides (ldhs) As Efficient Chloride Traps for Plasma Electrolysis Coatings

In this work, a layered double hydroxide (LDH) film intercalated with benzoate (C6H5COO−) anions was successfully fabricated on the porous surface of plasma electrolysis coating. For this purpose, the nitrate-loaded LDH (LDH-NO3) film grown on the plasma electrolysis film of aluminum alloy was immersed additionally in C6H5COONa solution. The results revealed that the intercalation of C6H5COO− anions into LDH film led to a more compact arrangement of the LDH flakes. The flake-like structure of LDH-C6H5COO film would act as smart reservoirs of C6H5COO− anions that are released on demand upon the onset of corrosion. Therefore, the LDH-C6H5COO film was found to exhibit significantly lower permeability to Cl− anions when compared to both plasma electrolysis and LDH-NO3 films, which emphasize the efficiency of LDH-C6H5COO film in delaying coating degradation and corrosion initiation. This result was attributed to the combined effects of Mg2+ and C6H5COO− ions released from LDH film.