The basic principle of a new approach of electrochemical noise (ECN) diagnostics, the Coulombs
counting method, is outlined, and the wide range of application as an online-monitoring tool in technical
corrosion systems is exemplified. It is shown that corrosion monitoring can be achieved with ECN
sensors as simple as monitoring temperatures. A special feature of this method is that corrosion in
crevices or under deposits can be investigated under real-time conditions. This allows monitoring the
efficiency of mitigation measures, e.g. application of corrosion inhibitors, under crevice corrosion
conditions. The new ECN diagnostic approach listens to the message of corroding systems and translates
it into technically relevant information.