Contribution to the discussion on pitting corrosion of stainless steels

Abstract

PITTING CORROSION generally takes the form of localised corrosive attack at closely defined points, whose area constitutes only a minute part of the total surface of the steel. The considerably higher rate at which the steel goes into solution at these points causes the cavities to grow in depth, and may ultimately result in perforation. Fig. 1. The rate of pitting corrosion is largely determined by the proportion of the total cathodic to the total anodic area. The anodic current and the cathodic current flowing in the corrosion cell are equal.