The Open Corrosion Journal

2009, 2 : 114-124
Published online 2009 April 07. DOI: 10.2174/1876503300902010114
Publisher ID: TOCORRJ-2-114

XPS Analysis of Passive Film on Stainless Steel

R. Natarajan , N. Palaniswamy , M. Natesan and V.S. Muralidharan
Corrosion Science & Engineering Division, Central Electrochemical Research Institute, Karai kudi, TN, 630006, India

ABSTRACT

Potentiodynamic, impedance measurements were carried out on 304 stainless steel in 0.5N, 1.0, 2.0 and 5.0 N H2SO4 solutions. X-ray photoelectron spectroscopic [XPS] studies carried out on 304 stainless steel in H2SO4 solutions revealed the existence of CrOOH, Cr2O3, γ-Fe2O3, γ- FeOOH, Mn2O3, Mn3O4, MnS, Ni (OH)2, Ni2O3, NiO, sulphides. The passive film found to contain chromium oxide inner layer and the dissolution of iron through it caused the formation of oxides of iron namely γ - Fe2O3 and γ-FeOOH. Higher oxides of manganese and nickel are also due to dissolution through the film. Sulphates are reduced to sulphur chemically by the released protons from anodic polarization.

Keywords:

304 stainless steel, passive film, impedance method, polarization, XPS studies.