Crevice Corrosion of Stainless Steels: II. Experimental studies

Abstract

Experimental studies have been carried out using crevices of Type 316 stainless steel freely exposed in chloride solutions. The characteristic behaviour of corrosion potential with time, together with morphological evidence, indicates a mechanism in which an induction period precedes the permanent breakdown of passivity and the initiation of active dissolution within the crevice.

On this basis electrochemical techniques have been developed for determining two parameters which, it is considered, characterise an alloy's resistance to the initiation of crevice corrosion. A mathematical model of crevice corrosion has been developed in Part I; when the electrochemical data are fed into this model encouraging agreement is found between the predictions of the model and the actual observations of crevice corrosion behaviour.The potential use of these techniques as a test method for assessing the resistance of alloys to crevice corrosion is discussed.