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

The effect of direct stray current on the degradation of epoxy resin coating in the environment with different pH values and chloride ion concentrations was studied by immersion test and electrochemical testing. The results show that the degradation of epoxy resin coating in the presence of direct current was accelerated. As the direct current (DC) interference voltage increased in the range of 1-5 V, the water absorption of the coating increased and the degradation was more serious. At DC interference voltage of 3 V the coating got the largest water absorption in neutral environment, but the degradation of the coating failed more easily in acidic environment. With the increase of chloride ion concentration the degradation of the coating became more serious and the water absorption increased first and then decreased.