Pretreatment and coating of low carbon steel using constant potential electrochemical process

Uniform and dense polyaniline-polypyrrole composite coatings were formed on low carbon steel using aqueous electrochemical process. The process involved three distinct stages: formation of an inorganic passive layer; dissolution of the passive layer; and formation of a polymeric coating. The development of the composite coatings on steel was studied by stopping the reactions at predetermined reaction times and analysing the coated samples using spectroscopic techniques. The chemical structures of the coatings were studied using infrared spectroscopy and the morphology of the coatings was studied using SEM. X-ray photoelectron spectroscopy was also used to study the elemental and chemical composition of the coatings.