Interpretation of Electrochemical Noise Generated by Multiple Electrodes

Abstract

To investigate the effects of galvanic coupling between dissimilar materials by electrochemical noise methods, an approach based on the use of an array of electrodes comprising two dissimilar pairs of identical electrodes is proposed. The individual currents flowing through each electrode are measured simultaneously with the potential of the array. For each electrode, the apparent noise resistance, , is determined from the square root of the potential variance divided by the individual current variance. For two dissimilar pairs of identical electrodes and under the assumption that nominally identical electrodes have identical resistance and are equally noisy, may approach closely to the true noise resistance of electrode n or be proportional to Rn. The analysis is facilitated by the introduction of “virtual electrodes,” corresponding to a convenient sub-array of real electrodes, and obtained by mathematical manipulation of the individual currents in the time or frequency domain. By using this approach, th...