The passive behaviour of ferritic stainless steel containing alloyed tin in acidic media

Abstract

The electrochemical behaviour and passive film properties of a new type of ferritic stainless steel containing alloyed tin in 0.5 M sulfuric acid solution were evaluated by a combined potentiodynamic curve, EIS and Mott–Schottky approach, with ex situ XPS and AES. The results revealed that the steel exhibits good passivity in sulfuric acid solution, and a very thin n-type, porous passive film was formed on the surface. The stability of the passive film decreased with increasing applied potential. Moreover, surface analytical results indicated that the surface formation of a Sn-rich oxide stable film (Sn²⁺ and Sn⁴⁺) can decrease its dissolution rate.