Effect of HCl on Pickling of 304 Stainless Steel in Iron Chloride-Based Electrolytes

By Li, Lian-Fu; Daerden, Mathieu; Caenen, Peter & Celis, Jean-Pierre
Published in NULL Elsevier Science 2006

Abstract

Publisher Summary This chapter presents a study in which the corrosion potential, weight loss, and surface finish of 304 stainless steel obtained in HCl electrolytes are investigated to unravel the role of HCl in a pickling. Weight loss and corrosion potential measurements and the surface finish is analyzed with SEM-EDX. The oxidized material is active on immersion, resulting in a low corrosion potential and a high weight loss. After certain duration, the material either remains active or passive depending on the HCl content. At low contents, an active-to-passive transition takes place, and localized corrosion at pits, grain boundaries, and honeycombed recesses is induced. The corrosion potential becomes high and the weight loss is suppressed. The corrosion potential of oxidized stainless steel is lowered after adding HCl, whereas the weight loss is decreased in initial stage and enhanced afterwards. When HCl is concentrated, the material always remains active and the weight loss increases linearly with time, as the surface tends to be brightening.

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