Use of a Liquid-Phase Ion Gun for Local Breakdown of the Passive Film on Iron

A silver/silver chloride microelectrode was developed as a liquid‐phase ion gun for investigation of precursor processes of pitting corrosion. This electrode was set as a probe electrode of a scanning electrochemical microscope and used to induce a local breakdown of passive film on iron. A small amount of chloride ions generated by cathodic polarization of the silver/silver chloride micro‐electrode has succeeded in inducing the local breakdown of the passive film formed on iron in deaerated pH 6.5 borate solution. Moreover, the microelectrode could detect ferric ions dissolved from the film at the initial stage of the film breakdown. © 2000 The Electrochemical Society. All rights reserved.