In this work, a new sensor system was developed based on an integrated multi-electrode technique in conjunction with an electrical resistance (ER) method. This new method has allowed galvanic currents flowing among the multi-electrodes and the total metal loss simultaneously measured. On the basis of the new designed 10 elements sensor system, the water-line corrosion in both static and flowing electrolytes were studied. It is found that in the static 3% NaCl aqueous condition, the major anodic area is located at the bot
tom of the sensor suggesting the water-line corrosion is controlled by the oxygen differential cell. However, in the flowing condition, the major anodic areas were close to the water line and the bottom region transferred to a cathodic area, suggesting that the flowing of the electrolyte is an important influence factor of the water-line corrosion. From the comparison of the galvanic current and the ER measurement results, it is seen that galvanic corrosion is the main contribution of the water-line corrosion in both static and flowing electrolytes.