Microelectrochemical polarization, thermodynamic calculations, and Auger electron spectroscopy were performed to elucidate the predominant factor affecting the pit initiation resistance at sulfide and carbosulfide inclusions in stainless steels. The Ti-oxide enriched layers on the inclusions inhibit the dissolution of the TiS and Ti4Ci2Si2 inclusions in the passive and trans-passive regions of stainless steels. While the MnS inclusion surfaces are covered by Mn-oxides, the corrosion resistance of Mn-oxides is not sufficient to prevent the inclusion dissolution and pit initiation. The oxide enriched surface layers on the sulfide and the carbosulfide inclusions greatly influence the pit initiation resistance at the inclusions.
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