Corrosion propagation monitoring using electrochemical noise measurements on carbon steel in hydrogenocarbonated solution containing chloride ions

The propagation of localized corrosion on API 5L X65 carbon steel in hydrogenocarbonated solution containing chloride ions was monitored during long immersion times by electrochemical noise (EN) measurements in ZRA mode. Monitoring corrosion propagation from the EN amplitude is possible but interpreting the potential and current transients after long immersion times is made difficult by the different corrosion processes (metastable or stable pits, crevices, corrosion products detachment…) occurring simultaneously. The noise impedance at 0.1 Hz, directly derived from the EN measurements, is shown to decrease and stabilize in the same time scale as the coupled potential of the electrodes.