Noise Resistance Applied to Corrosion Measurements: IV. Asymmetric Coated Electrodes

Corrosion monitoring based on noise‐resistance measurements in cells with two working electrodes assumes that both electrodes have identical impedance. Asymmetry in the electrode impedances may appear in particular corrosion systems, such as coated electrodes. A theoretical model taking into account this asymmetry is developed from previous work done in our laboratory. It allows calculation of the current noise generated by corrosion processes and of its partition on each electrode. It also allows corrosion occurring only on one electrode to be distinguished from corrosion occurring on both. Experiments carried out on anodized aluminum electrodes have confirmed all the predictions of the model.