S Khafanj - Color Engineering Dept., Iran Khodro Diesel Company Polymer Engineering Dept., Amirkabir University of Technology
M.M Attar - Polymer Engineering Dept., Amirkabir University of Technology
R Naderi - Polymer Engineering Dept., Amirkabir University of Technology National Petrochemical Company-Research and Technology, Iran Polymer and Petrochemical Institute, Tehran, Iran

The influence of the coating thickness and electrolyte concentration parameters on cathodic disbondment of polyurethane coating applied on solvent degreased mild steel was assessed using electrochemical impedance spectroscopy (EIS) at open circuit potential (OCP). In order to polarize the samples, sacrificial magnesium anode imposing potential -1.46VAg/AgCl was employed. Through taking advantage of polarization resistance as well as total impedance extracted from EIS data, coating thickness and electrolyte concentration revealed a significant impact on the diffusion mechanism.

EIS, Polyurethane, Mild steel, Cathodic disbanding, Solvent degreasing