Repassivation Behavior and Properties of Passive Films of Duplex Stainless Steels in Chloride and Thiosulfate Containing Environment

Abstract In this paper, the repassivation kinetics of lean duplex stainless steels in environments containing chloride as well as thiosulfate ions was studied through the scratch test method. The austenite or the ferrite phase was selectively dissolved from the commercially available alloys and the remaining phase was used to study the repassivation behavior through scratch test as well as the defect density within the passive film through Mott-Schottky analysis. Results from this study have provided insights into the effect of microstructure and chemical composition on the repassivation mechanisms as well as passive film properties of lean duplex stainless steels.