THE ROLE OF OHMIC POTENTIAL DROP IN THE INITIATION OF CREVICE CORROSION ON ALLOY-625 IN SEAWATER

Analysis of the literature reveals that little attention has been paid to the role that IR, or ohmic potential, drop plays in initiating crevice corrosion. In the following paper experimental evidence supporting an IR-induced crevice corrosion mechanism for alloy 625 in seawater is presented and discussed. Depassivation of the metal within the crevice results when the IR drop down the crevice becomes large enough to force the crevice to reside at a potential where passivity is destroyed and active dissolution of the metal occurs.