| Electrochemical Noise (EN) Technique has been developed quickly during these years. It makes sense to broaden the application areas of EN technique by electrodes system designing, especially in the area of on-line corrosion monitoring of structural material in nuclear electricity industry and metal in seawaters. Six different kinds of materials were chosen as the coupling electrode. The surface area ratio of working electrode and coupling electrode, under which EN measurement can be actualized, was confirmed based on experiments. By these approaches coupled asymmetry electrodes system fit for on-line EN monitoring was built successfully. The electrodes system was applied in two areas. EN measurement of C-ring specimen with Stress Corrosion Cracking (SCC) was carried out. Results showed that from the characters of spikes in time records of the potential and current, asymmetry distribution of EN signal, fitting value of PSD linearity section and frequency of events (fn), different corrosion states of C-ring specimens can be distinguished. At the same time, it was observed that the potential of sensitized 304SS C-ring specimen in 0.5mol/LNa2S2O3 solution of room temperature fell intensively in a few hours, accompany with the increasing of local corrosion susceptibility. Furthermore, EN measurement of steel specimen in tidal zone and emerged zone in sea waters was tried out. Parameters showed corrosion type of steel specimen in tidal zone and emerged zone was mainly general corrosion, and EN measurement of metal material in seawater was useful. Results of experiments reflect the advantages of the electrodes system built, and make good preparation for on-line monitoring.
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