Study on diffusion of NaOH solution in zinc-rich epoxy coating using EIS

Abstract

In order to explore the diffusion process of NaOH solution in zinc-rich epoxy coating, in this paper, conventional three-electrode system was used to test the open circuit potential and electrochemical impedance spectrum, and equivalent electric circuit was fitted to get the related parameters including capacitance, resistance, phase angle and et al to reveal the diffusion process. The results show that three stages are divided including diffusion in coating, finite layer diffusion and double layer diffusion, and two criterions are put forward.