Corrosion and Passivation Studies of Iron and Ferrous Alloys
Abstract
Corrosion and passivation of iron and ferrous alloys is an important subject in many disciplines from both theoretical and practical points of view. Corrosion, and particularly passivation, however, is poorly understood despite extreme efforts. The purpose of this work is to understand the mechanism of passivation film formation and reduction, also the structure of passive film. The in-situ electrochemical techniques such as combined cyclic voltammetry and rotating ring disk electrode have been used in different pH of borate buffer solution. Both cyclic voltammetry and potential pulse techniques showed that during passive film formation, the ferrous ions enter into the metal solution interface, which causes a formation of a deposited over-layer on surface of the passive film. In-situ Raman spectroscopy has been used to elucidate the structure of the passive film on iron. The Raman spectra of this film showed several peaks at low frequency (200-800 per cm) which is not the same as any known stoichiometric iron oxides or oxy-hydroxides. In addition, Raman spectroscopy for air oxidized iron-chromium alloys also has been used. The result showed that this technique can be used to study the dry corrosion as well as wet corrosion. Transmission electron microscopy of the passive film on iron showed that the passive film on iron has crystalline structure and also there are some epitaxial relationships between oxide and iron substrate.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 15, 1981
- Accession Number
- ADA116422
Entities
People
- B. D. Cahan
- Ernest B. Yeager
- Gholamabbas Nazri
Organizations
- Case Western Reserve University