USING WBE CONJUNCTION WITH ELECTROCHEMICAL NOISE TO EVALUATE THE CORROSION REGULARITY OF ENAMEL COATING MODIFIED ON MILD STEEL IMMERSED IN CORROSIVE SOLUTION

In this paper, the development and the formation of the mild steel immersed in seawater that covered with enamel coating are investigated. The wire beam electrode (WBE) was applied to evaluate pitting corrosion and local inhomogeneous corrosion that happened on the coated surface of metal substrate. This method can obtain Maps that can show corrosion potential and galvanic current distributions and the specific values can be calculated from the WBE surface that was covered by enamel coating. Corrosion potential–current and electrochemical noise were successfully measured by using a WBE scanner and electrochemical workstation. This new linkage-test method means that the combined WBE-Rn has ability to characterize and analysis the process of enamel coating failing more accurately [Ref. 1; Ref. 2; Ref. 3; Ref. 4]. To some extent, the method can also predict the tendency and location of corrosion occurring. It was found that the coating has a good protective effect on the surface of the metal substrate because the corrosion potential is very positive and the corrosion current is very small. At the same time, in the course of the test, the distribution of the anode current is heterogeneous, as time increases, the original single anode current region gradually expands and is connected with the other anode regions in the final. In addition, corrosion often occurs at the boundary of the electrode (WBE) and then to the central area.