Comparative study of the surface oxide films on lean duplex and corresponding single phase stainless steels by XPS and ToF-SIMS.

Highlights • Duplex stainless steel and corresponding single phase alloys are compared. • The native oxide films formed after mechanical polishing are studied. • A coupling of XPS and ToF-SIMS is used. • The thickness, composition and chemical states of the oxide layer are investigated. • The link between the chemical compositions of the bulk and the surface is discussed. Abstract The surface oxide films formed after mechanical polishing on duplex stainless steel and corresponding single phase alloys were characterized by XPS and ToF-SIMS. The native oxide films are mixtures of oxides and hydroxides composed of Fe(III), Mo(IV) and Mo(VI) in the outer region and Cr(III) in the inner region. Nickel, molybdenum and nitrogen are enriched in the underlying metal while chromium and molybdenum are enriched in the oxide layer. The contents of alloying elements in the oxide layer and/or in the underlying metal are found to be directly related to their content in the bulk of the alloys. [ABSTRACT FROM AUTHOR]