New Methods of Quantitative Analysis of Localized Corrosion Using Scanning Electrochemical Probes

A new commercially-designed instrument using the Scanning Reference Electrode Technique (SRET) has enabled the measurement of localized cutrent densities in the vicinity of pits in a stainless steel in natural seawater. The instrumentation is described in detail, together with the novel techniques used to calibrate the system and convert variations in local voltage, resulting from the ion flux close to surfaces, into localized current densities. Novel applied potentiodynamic pitting scans have been obtained for localized areas immediately adjacent to accurately defined regions of electrode surfaces. New techniques such as this is essential if improved models of localized corrosion are to be developed.