Characterisation of surface film on iron samples treated with octadecylamine

AbstractThe anticorrosion performance of the surface film on octadecylamine (ODA) treated iron in electrolytes containing chloride, sulphate and carbonate ions was studied by electrochemical impedance spectroscopy (EIS). The EIS measurements for iron samples treated with various ODA concentrations revealed that the highest corrosion resistance appeared at 25 mg L−1, at which the R p and C f values reached the maximum and the minimum respectively. It was shown from auger electron spectroscopy (AES) that the surface film of the iron sample at 25 mg L−1 ODA consisted mainly of three layers: outer pure ODA, middle mixed ODA iron oxides and inner iron oxides. The infrared specular reflection spectrometry indicated that the pure ODA layer on the surface film was not monomolecular and its thickness was related to the ODA concentration.