Influence of the doping agent on the corrosion protection properties of polypyrrole grown on aluminium alloy 2024-T3

The corrosion protection properties of polypyrrole (PPy) electrodeposited onto aluminium alloy 2024-T3 substrates were investigated as a function of the doping agent. We used camphor sulfonic acid (CSA), para toluene sulfonic acid (p-TSA), phenylphosphonic acid (PPA), oxalic acid (OA) and cerium nitrate salt (Ce(NO3)3) as doping agents. The resulting coatings have been evaluated towards corrosion protection of aluminium alloy 2024-T3 using electrochemical impedance spectroscopy (EIS). Complementary, scanning electron microscopy (SEM) provided images on the morphology and the thickness of the coatings. The results showed that coatings formed using Ce(NO3)3 solution protect the substrate more efficiently compared to the other coatings.