The study of the localized corrosion caused by mineral deposit using novel designed multi‐electrode sensor system

Abstract

In this paper, a new kind of multi‐electrode sensor system was developed for the study of the localized corrosion of the X65 pipeline steel caused by mineral deposit in oxygen containing solution. The electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were simultaneously used for the monitoring of the corrosion depths and galvanic currents. The new sensor system showed a wider application range in the monitoring of the corrosion depth compared with traditional electrochemical methods. It also presented high measurement accuracy in the corrosion depth measurement. The test results revealed that the mineral deposit and heterogeneous distribution of the rust layer on the steel surface will cause inhomogeneous corrosion process. The deposit‐covered area will always act as anode and serious localized corrosion will occur beneath the sand particles. The ER method is not an in situ monitoring technique. The excitation current used in ER measurement will lead to a charging and discharging process of the double electrolyte layer on the steel surface.