The non-intrusive use of EN for corrosion monitoring is very attractive, e.g. aircraft corrosion and gas scrubbing tower monitoring examples. Fluctuations of potential or current of a corroding metallic specimen are a well known and easily observable phenomenon and the evaluation of EN as a corrosion tool has increased steadily since Iverson's paper in 1968.
The extensive development in the sensitivity of the equipment for studying electrochemical systems has rendered the study of oscillations in electrochemical processes, that translate into measurable EN, increasingly accessible. The study of corrosion potential fluctuations was applied, for example, to monitor the onset of events characterizing localized corrosion such as pitting or stress corrosion cracking (SCC), exfoliation, erosion-corrosion in either laboratory or diverse and complex industrial environments. No other technique, electrochemical or otherwise is even remotely as sensitive as EN to system changes and upsets.
During localized corrosion EN is believed to be generated by a combination of stochastic processes, such as passivation breakdown and repassivation events, and deterministic processes which can be caused by film formation or pit propagation processes.