Evaluation of protecting properties of epoxy coatings on navy steel by electrochemical impedance espectroscopy

Electrochemical Impedance Spectroscopy (EIS), open circuit potential (o.c.p.) measurements and saline fog chamber experiments were employed to study the protective action of four epoxy coatings on navy steel immersed in artificial seawater. From EIS data such as pore resistance, coating capacitance, and the use of the proper electric equivalent circuits it was possible to obtain information regarding the corrosion behavior under each coating. Results have been interpreted under the assumption that it is possible to predict the lifetime of conventional paintings as compared with chemically modified coatings. After 40 days of immersion, variable results between electrochemical experiments and saline fog chamber experiments were obtained.