Investigation the corrosion protection of mild steel by polypyrrole film prepared in 10-camphorsulfonic acid solution by electrochemical method

Polypyrrole (PPy) was prepared on the mild steel CT3 by electrochemical polymerisation in a solution containing pyrrole monomer, 10-camphorsulfonic acid and molybdate dopant anions. The mild steel surface was passivated before electropolymersation in a solution of sodium molybdate 0.1 M. The morphology and structure of the PPy film were studied by electron scanning microscopy (SEM). The typical cauliflower structure of PPy was observed. Raman spectroscopy showed that the obtained PPy was in oxidized state. Energy-dispersive X-ray spectroscopy (EDX) indicated that molybdate anion was doped in the PPy film. The thermal stability of PPy was investigated by TGA, showing that PPy was stable at higher than 500 ^oC. The corrosion behavior of mild steel (CT3) with PPy film in solution of NaCl 3 % were studied by electrochemical impedance spectroscopy (EIS) and other electrochemical methods. The presence of molybdate dopant anion in PPy improved the corrosion protection of mild steel. (author)