Polypyrrole and polypyrrole-tungstate electropolymerization coatings on carbon steel and evaluating their corrosion protection performance via electrochemical impedance spectroscopy

Polypyrrole (PPy) and polypyrrole-tungstate (PPy-WO42−) coatings with excellent adherence properties were electropolymerized on carbon steel using oxalic acid solutions containing pyrrole and pyrrole-tungstate, respectively. The electropolymerizations were carried out using cyclic voltammetry at the scan rate of 20 mV s−1. Electrochemical impedance spectroscopy (EIS) was also used to evaluate the performance of two kinds of polypyrrole coatings on carbon steel surfaces under immersion in a 3.5% sodium chloride (NaCl) solution. Corrosion potentials as well as impedance data were obtained for each coating after various immersion times. Obtained results revealed that PPy-WO42− coating provided a noticeable protection enhancement against corrosion progression.