Polyaniline-lignosulfonate/epoxy coating for corrosion protection of AA2024-T3

Abstract Corrosion protection arising from epoxy coatings incorporating lignosulfonate-doped polyaniline (Pani-LGS) upon AA2024-T3 was studied in 0.6 M NaCl. Synthesized Pani-LGS particles were investigated using TEM, FTIR, TGA and conductivity, whilst coatings were also physically examined using SEM. The coating performance was studied using a combination of potentiodynamic polarisation, EIS, FTIR spectroscopy and X-ray photoelectron spectroscopy. The performance of Pani-LGS/epoxy blends is discussed more generally, with tests revealing that on exposure to 0.6 M NaCl solution for 30 days, a 5 wt% Pani-LGS/epoxy coating resulted in low levels of corrosion. A mechanism for the postulated mode of corrosion protection is presented.