Corrosion behaviors and physical properties of polypyrrole-molybdate coating electropolymerized on carbon steel

Polypyrrole (PPY) and polypyrrole-molybdate (PPY-MoO42-) coatings have been successfully electro-polymerized on carbon steel by cyclic voltammetry method in aqueous oxalic acid solutions. These coatings were characterized by FTIR, XPS, EDX, FESEM and AFM methods. It was found that the incorporation of MoO42- enhanced the corrosion resistance of PPY coating and improved the physical properties, such as thermostability, wettability, adhesion and hardness. The corrosion protection performance of PPY and PPY-MoO42- coated steel in 0.1 M HCl solution was investigated by electrochemical impedance spectroscopy and Tafel polarization. Moreover, molecular dynamic simulations were engaged to assess the interactions between the metal surface and complex coatings. The exceptional anti-corrosion performance of PPY-MoO42- coating was associated with the complex passive film on the metal surface and the barrier effect of the coating.