Corrosion protection of mild steel in natural sea water, by protective organic coatings and rapid assessment using an electrochemical impedance spectroscopy (EIS)

Abstract

Electrochemical impedance spectroscopy (EIS) as well as open circuit potential (OCP) of both bare and complete epoxy system coated mild steel panels, have been conducted in natural sea water environment. All obtained electrochemical impedance spectroscopy parameters such as corrosion current densities (icorr.), corrosion potential Ecorr, quantitative corrosion rate (CR), charge transfer resistance (Rct) and double layer capacitance (Cdl) of both bare and coated mild steel panels have been compared, discussed and presented. Comparisons between open circuit potential curves, Nyquist and bode plots of both bare and different conditions of epoxy coated mild steel have been plotted and presented. Potentiodynamic polarization measurements have been also performed, on bare mild steel and all obtained electrochemical parameters are presented. The bare mild steel obtained corrosion protection efficiency (PE) % using the organic protective coatings has been calculated and found to be approximately 100%.