A TIME-DOMAIN APPROACH TO EXTRACTING POLARIZATION RESISTANCE FROM ELECTROCHEMICAL NOISE DATA

Abstract

Measuring the corrosion rate of a corroding metal is of interest in many situations including monitoring industrial processes and fundamental research in laboratories. The corrosion rate of a metal can be measured electrochemically by determining its polarization resistance, which is inversely proportional to the corrosion rate. What is introduced in this letter is a novel technique for extracting polarization resistance from electrochemical noise (EN) data. An advantage of this approach is that very short time records, of the order of a few seconds, can be assessed to see if they reveal a polarization resistance. The theoretical framework for this approach is based on a time-domain analysis of an electrical circuit model of an EN experimental arrangement. The analysis indicates that polarization resistance can be interpreted only if one electrode, not both electrodes, is predomi-nately generating electrochemical transients during a given time record. An algorithm for extracting polarization resistance from EN measurements is described and examples of its implementation on EN data support the features of the theoretical framework.