Electrochemical synthesis and Evaluation of corrosion behavior of novel Polypyrrole -MMT nanocomposites on mild steel

The need for toxic chromate replacement in metal finishing industries has prompted an intensive search for replacement technologies in recent year [1-4]. Conductive polymers have emerged as an outstanding, environment friendly corrosion protectors of metal substrates for replacing the conventional chromate treatments. It has been recently demonstrated that electrodeposition of conductive films specially, nanocomposite of them on metal surfaces results in improvement of corrosion protection compared to the conventional coating methods like dip coating and spray coatings. The main purpose of this work is , the understanding of electro syntheses of Polypyrrole (ppy) and nanocomposite polypyrrole-organoclay-montnorillonite (Ppy-MMT) on mild steel electrodes by using galvanoestatic technique from an aqueous oxalic acid solution. Intercalation of MMT in composite coatings leads to increase of the coating resistance against corrosion. Protective performance against the corrosion of these coatings is evaluated by using an open circuit potential monitoring, Polarization and electrochemical impedance spectroscopy (EIS) techniques in a corrosive solution (3.5% NaCl). It was observed that polypyrrole-MMT coating on mild steel was the best system for corrosion protection when compared to polypyrrole on mild steel. It has also been proved that uniformity and better control over the thickness of the coating can be achieved by electro deposition