Development and in-situ application of a novel pH sensitive microelectrode in crevice corrosion

The study of localized corrosion is hindered by the inability to characterize electrolyte compositions inside crevices and pits during the corrosion process. This paper describes the development of a microelectrode system for in-situ monitoring of the pH in artificial crevices and small recesses. This system permits the determination of the pH gradient inside a crevice, even in the presence of a pronounced potential drop. The pH sensor, consisting of a palladium hydride electrode, can be positioned at any desired depth into the crevice. With increasing time of crevice corrosion one finds a pronounced pH change in the crevice electrolyte. This work lends further insight towards the understanding of crevice corrosion and other localized corrosion phenomena.