Electrochemical study of polyaniline coating electropolymerized onto AA2024-T3 aluminium alloy: Physical properties and anticorrosion performance

Chronoamperometry was used to deposit polyaniline (Pani) films onto AA2024-T3 aluminum alloy from a sulphuric acid electrolyte. Electropolymerization parameters of 1.00 VSCE and 17 min produced a Pani coating with the highest protection ability in 0.5 M NaCl solution. Structure and morphology of the coating were characterized by scanning electron microscopy (SEM) and infrared spectroscopy under reflectance mode (FTIR-ATR) analysis. Electrochemical impedance spectroscopy (EIS) was applied to access the physical proprieties and the anticorrosion performance of Pani in 0.5 M NaCl solution. Impedance spectra, collected at open circuit potential (OCP), exhibited, at high frequencies, a CPE contribution related to inhomogeneous water uptake in the coating which was analyzed by normal power-law distributions of the local resistivity and permittivity of coating. Finally, the Pani anticorrosion performance was discussed.