In situ X-ray absorption near edge structure study of the potential dependence of the formation of the passive film on iron in borate buffer
Journal Article
·
· Journal of the Electrochemical Society
- Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science
- Univ. of Manchester (United Kingdom)
The passive film formed on iron in pH 8.4, 0.136 M borate buffer over a broad potential range was characterized by in situ x-ray absorption near edge structure. On stepping the potential to a value between {minus}0.6 and +0.4 V relative to a mercurous sulfate reference electrode (MSE), a passive film forms without detectable dissolution. Formation of a passive film at potentials between {minus}0.8 and {minus}0.65 V is accompanied by dissolution during the early stages of passivation. At {minus}0.9 V, the iron did not passivate, but continued to dissolve. The valence state of iron i the film is predominantly Fe{sup 3+} with 4 to 10% Fe{sup 2+} at high potentials (+0.4 V), and 14 to 20% Fe{sup 2+} at the lower potentials. The behavior on changing the solution concentration (pH 8.4, 0.01 M) and pH (pH 7.4, 0.1 M) was compared with passivation in the classical borate buffer (pH 8.4, 0.136 M). Passivation at +0.4 V in the modified borate buffers is associated with dissolution during the early stages of passivation, but the films that form have average oxidation states similar to those observed in pH 8.4, 0.136 M borate buffer. This indicates that the susceptibility to dissolution during passivation does not influence the valence state of the final film.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 533118
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 7 Vol. 144; ISSN 0013-4651; ISSN JESOAN
- Country of Publication:
- United States
- Language:
- English
Similar Records
In situ XANES study of the passive film formed on iron in borate buffer and in sodium acetate
CATHODIC REDUCTION OF PASSIVE FILMS ON IRON IN BORATE AND PHOSPHATE BUFFER PH 8.4: DIFFERENT MECHANISMS REVEALED BY IN SITU TECHNIQUES.
CATHODIC REDUCTION OF PASSIVE FILMS ON IRON IN BORATE AND PHOSPHATE BUFFER PH 8.4: DIFFERENT MECHANISMS REVEALED BY IN SITU TECHNIQUES.
Conference
·
Mon Dec 30 23:00:00 EST 1996
·
OSTI ID:475596
CATHODIC REDUCTION OF PASSIVE FILMS ON IRON IN BORATE AND PHOSPHATE BUFFER PH 8.4: DIFFERENT MECHANISMS REVEALED BY IN SITU TECHNIQUES.
Conference
·
Sat Mar 24 23:00:00 EST 2001
·
OSTI ID:782048
CATHODIC REDUCTION OF PASSIVE FILMS ON IRON IN BORATE AND PHOSPHATE BUFFER PH 8.4: DIFFERENT MECHANISMS REVEALED BY IN SITU TECHNIQUES.
Conference
·
Sat Mar 24 23:00:00 EST 2001
·
OSTI ID:780779