An electrochemical evaluation on the crevice corrosion of 430 stainless steel by micro capillary tubing method

The aim of this study was to investigate the initiation of crevice corrosion for ferritic 430 stainless steel in artificial crevice electrode cells using the IR drop mechanism. The 430 stainless steel artificial crevice electrodes were potentiodynamically polarized in solutions of sodium chloride with different concentrations. The potentiostatic polarization was measured for various artificial crevice sizes by measuring the potentials in the crevice by the depth profile technique using a micro capillary tube which was inserted into the crevice. The criterion for IR> ∗, where ∗ is the difference between the applied potential, ESURF, and the electrode potential of the active/passive transition, EA/P, was also measured during the process of crevice corrosion. The potentials in the crevice were successfully measured from −220 mV versus SCE to −360 mV versus SCE, which is lower than that of the external surface potential of −200 mV versus SCE. Thus these results show that evaluation of corrosion using the IR drop mechanism in the crevice was more objective and easier to reproduce than the existing methods. C 2006 Springer Science + Business Media, Inc.