Studies on corrosion protection of Al2024 T6 alloy by electropolymerized polyaniline coating

Aqueous electropolymerized polymer coatings on aluminum alloys can replace the carcinogenic chromate coating. In this work, the corrosion protection ability of electropolymerized polyaniline coating on Al2024 T6 alloy has been found out. The polyaniline coatings on aluminum were formed by galvanostatic and potentiostatic methods from a bath of 0.5 M oxalic acid containing 0.1 M aniline. The corrosion protection ability of the coating was found out by Tafel polarization and EIS in 1% NaCl solution. It has been found that polyaniline coated aluminum alloy has exhibited higher corrosion activity due to the presence of pores in the coating. However, the corrosion resistant property of polyaniline coated aluminum has been found to be improved to 90% by post-treatment in cerium containing solution at 60 °C.