Effect of Alternating Stray Current on Degradation of Epoxy Resin Coating in Immersion

The effect of alternating stray current on degradation of epoxy powder coating in environments with different pH values and chloride ion concentrations was studied by weight loss method, polarization curves and electrochemical impedance spectroscopy. The experimental results show that the degradation of epoxy powder coating in the presence of alternating current (AC) was faster than that without AC interference. With the AC interference voltage increased in the range of 1-5 V, the water absorption of the coating increased and the corrosion of the substrate metal was more serious. When the AC interference voltage was 3 V, the acidic environment and the increase of chloride ion concentration made the degradation of the coating happen more easily and made the metal substrate corrode more seriously.