An Epoxy Based Lignosulphonate Doped Polyaniline-Poly(Acrylamide Co-Acrylic Acid) Coating for Corrosion Protection of Aluminium Alloy 2024-T3

Corrosion protection arising from epoxy coatings incorporating lignosulfonate-doped polyaniline-poly(acrylamide co-acrylic acid) (Pani-PAmAc) upon AA2024-T3 was studied in 3.5% NaCl. Synthesised Pani-PAmAc particles were investigated using TEM, FTIR, TGA and conductivity, whilst coatings were also physically examined using SEM. The corrosion performance of coatings was studied using a combination of potentiodynamic polarisation, EIS, and salt spray test. Results reveal that the epoxy based Pani-PAmAc coating was smooth and continuous. Potentiodynamic polarisation, EIS and salt spray testing revealed significant corrosion protection even after 50 days exposure to a 3.5% NaCl environment. This was attributed to the synergistic effect of polyaniline with poly(acrylamide co-acrylic acid) which prevented dopant loss and maintained electronic conduction even after long term exposure to a corrosive environment