Mapping non-uniform corrosion using the wire beam electrode method. II. Crevice corrosion and crevice corrosion exemption

Abstract

A wire beam electrode (WBE) was used to study corrosion of steel (UNS no. G10350) under carbon dioxide and oxygen environments with the presence of an artificial crevice. Local electrochemical parameters were measured directly from crevice areas and were used to calculate local corrosion rates and their distributions. Electrochemically calculated corrosion maps were found to be quantitatively comparable with microscopic observation of corroded electrode surface. It was also found that the WBE– R n method has a limitation when applied to oxygen corrosion in a stagnant electrolyte. An alternative method, which is based on galvanic currents, was employed for corrosion rate calculation. Under oxygen environment, localised corrosion was found to concentrate on crevice areas, while under carbon dioxide environment, crevice corrosion was not observed. This work confirms the applicability of the WBE method in crevice corrosion studies.