The electrochemical synthesis of polyaniline on stainless steel and its corrosion performance

Polyaniline (PANI) coatings were synthesized on stainless steel electrode by applying two different scan rates (10 and 50 mV s−1) in 0.1 M aniline containing 0.3 M oxalic acid solution. The synthesized polymer films were strongly adherent and homogenous in both cases. The corrosion performances of polyaniline coatings were investigated in 0.1 M HCl solution, by using electrochemical impedance spectroscopy. Also, the open circuit potential–time (Eocp–t) diagrams were used. It was shown the polymer film deposited at low scan rate exhibited a better barrier property than the polymer film produced high scan rate. The PANI film coated at low scan rate provided important protection to stainless steel for longer periods, in such aggressive medium. Also, it was found out that the polymer film coated at low scan rate decreased the corrosion rate, by its catalytic behaviour on formation of ferric and chromium oxide layers.