Investigation of corrosion resistance property and passivation film structure of tin containing stainless steel

The effects of Sn on the corrosion resistance and the passivation film structure were investigated. The relation between the corrosion resistance and the microstructure was established. The results from X-ray photoelectron spectroscopy analysis indicate that tin exists in the outer layer of passivation film mainly in the form of SnO2, and there is a tin rich region in the inner layer. The enrichment of tin in the metal/oxide interface will improve the stability of the passivation film, raise the pitting potential and reduce the corrosion current density. The enrichment of tin around the sulphide inclusions will help form tin rich layer and release the pitting corrosion caused by sulphide.