Corrosion Potential Monitoring

The measurement of the corrosion potential is a relatively simple concept, with the underlying principle widely used in industry for monitoring reinforcing steel corrosion in concrete and structures such as buried pipelines under cathodic protection. Monitoring of anodic protection systems is a further application area. Changes in corrosion potential can also give an indication of active/passive behavior in stainless steel. Furthermore, when viewed in the context of Pourbaix diagrams, the corrosion potential can give a fundamental indication of the thermodynamic corrosion risk.

The corrosion potential is measured relative to a reference electrode, which is characterized by a stable half-cell potential. The electrochemical details of important reference electrodes are available here. Corrosion potential measurements are usually classified as an intrusive indirect method. Either a reference electrode (and possibly a separate sensor of the material to be monitored) has to be introduced into the corrosive medium for these measurements, or an electrical connection has to be established to a structure in conjunction with an external reference electrode.