The electrochemical study of the epoxidic films, electrodeposited on carbon steel

Abstract

This paper presents the results of the electrochemical measurements regarding the epoxy films electrodeposited on carbon steel. Nyquist and Bode diagrams were recorded for various immersion periods in 3% NaCl solution, using the open circuit potential method; their interpretation allows us to modell the corrosion process of carbon steel substrate under epoxy films with an electric equivalent circuit, which has two time constants. Epoxy film capacitance and resistance were monitored with immersion time emphasizing a low water permeability of films and respectively a reduced ionic transport in these films. Anodic polarization curves show low dissolution current densities and in consequence efficiency of the protective films does not decrease in time below 90%.