Synchrotron-based near ambient-pressure X-ray photoelectron spectroscopy and electrochemical studies of passivation behavior of N- and V-containing martensitic stainless steel

Abstract

Passivation behavior of a N- and V-containing martensite stainless steel was studied by synchrotron-based near ambient-pressure X-ray photoelectron spectroscopy, electrochemical analyses, and thermodynamic calculation. The passive film consists of Cr3+, Fe(2, 3)+, and V(2, 3, 4)+ oxides as inner layer, and Cr3+ and Fe3+ hydroxides as outer layer. Austenitization at 1080 oC (rather than 1010 oC) and anodic polarization facilitate transformation of CrN to Cr2O3 leading to further enrichment of Cr3+ oxide in the passive film. Whereas higher Cl- concentration promotes film dissolution leading to higher level of point defects and higher fraction of remaining V oxides in the passive film.