In order to investigate the effect of adhesion on ionic resistance of coatings, non-pigmented epoxy/polyamide free film and applied coating were compared. The results obtained from electrochemical impedance spectroscopy (EIS) after various immersion times in 3.5 wt% sodium chloride solution showed that the corrosion resistance of the free film attached to the steel surface was by approximately one order of magnitude less than the applied one, indicating the important role of adhesion on the anti-corrosion properties of coatings. For the applied coating, the first signs of corrosion products appeared after 20 days of immersion, while this time was reduced to merely 2 days for the attached free film. Coating capacitance data pointed out that saturation with water for the attached free film was faster and also the amount of absorbed water was higher than the applied coating. Gravimetric water uptake of epoxy/polyamide free film was also determined and compared via EIS data. In addition, epoxy/polyamide free films were placed as membranes against NaCl and KCl solutions with different concentrations. The concentration of alkaline ions in the solution was measured using the flame photometry technique. Among epoxy membranes, the degradation of the sample which faced 3.5 wt% NaCl was more remarkable comparing EIS and FT-IR analysis.