The influence of the metallic surface treatments on the corrosion behaviour of the metal/organic film interface

Abstract

This paper presents the results regarding the influence of the metallic surface treatments on the corrosion behaviour of the metal/organic film interface. Electrochemical impedance spectroscopy (EIS) and stepwise polarisation have been used. The measurements were carried out in acid, neutral and alkaline solutions at 25degreesC temperature during a 5000 hours period. The interpretation of the impedance spectra has permitted the modelling of the carbon steel/organic film/electrolyte system with the electrical equivalent circuits. The protective properties of the tested systems from the principal elements of equivalent circuit were evaluated. The electrochemical parameters of metallic substrate were determined from the anodic polarisation curves. The results emphasised that the use of a phosphating primer layer before the deposition of the organic film increases the film adhesion to the metal surface and improves the corrosion behaviour of the carbon steel/organic film interface.