A New Method for Corrosion Current Measurement: the Dual-Electrochemical Cell (DEC)

Abstract

This paper presents the “dual electrochemical cell” (DEC) method, a new technique that allows monitoring of corrosion current ( i corr ) in real time with a corrosion potential E corr that may change with time. In this method, the E corr of a metal corroding in a solution containing the oxidant of interest is measured in the 1st cell. This potential is then continuously applied in real time to a second cell using the same metal electrode in the same solution but free of the oxidant, and the current of the 2nd cell, which represents the i corr of the 1st cell, is monitored. This setup allows direct measurement of i corr without having to polarize the corroding electrode away from E corr . The advantages of DEC over conventional methods are that it does not require the corroding system to be at steady state, and avoids any ambiguities associated with the extrapolation of the measured current-potential relationship to extract i corr . The i corr values obtained using the DEC method were compared with those obtained using conventional polarization techniques, using dissolved metal concentrations and surface analysis observations, and the results showed that the DEC method provides the most accurate measurement of i corr .

Periodic aggregation patterns of oxide particles on corroding metals: chemical waves due to solution feedback processes

“…We have also previously reported the oscillatory behaviours of corrosion potential and corrosion current during carbon steel corrosion in aerated solutions at near neutral pH. 64 This study builds on the existing work and provides unequivocal evidence for the systemic feedback in corrosion. This work is the first to clearly show that the non-uniform deposition of metal oxides during corrosion can occur via strongly coupled solution reactions and transport processes, and not simply as a result of metallurgical non-uniformity or localized solution environments.…”

Surface electroanalytical approaches to organic polymeric coatings

“…New and improved electroanalytical methods are also currently being developed with benefits of faster acquisition and real-time monitoring of relevant corrosion parameters. The dual-electrochemical-cell method, 84 electrochemical frequency modulation 85 and scanning electrochemical cell microscopy 86 are a few emerging techniques that show promising use for polymer coating investigation.…”

EMAR monitoring system applied to the thickness reduction of carbon steel in a corrosive environment

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