Ward, Michael C. L. (1986) An EXAFS structural study of the passive films formed on Fe-Cr alloys. PhD thesis, University of Warwick.

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Abstract

Comparatively little is known about the nature of the passive films formed
upon the technologically important iron-chromium alloys. It is known
however, that they are both very thin (50A) and possibly amorphous: as such
they are difficult to characterize by conventional diffraction methods. To
avoid the problems associated with the diffraction techniques, the EXAFS
technique has been used to characterize the passive film.
Iron-chromium alloys containing up to 29% atomic chromium were passivated in
0.1M NaNO2, 0.05M K2CrO4 and 2.0M H2S04. X-ray absorption measurements were
then made upon the passivated alloys, using both total electron yield and
fluorescence yield to determine the X-ray absorption.
Analysis of the extended X-ray absorption fine structure has revealed that
an increase in structural disorder of the passive film may be correlated
with an increase in the chromium content of the alloy. It has been shown
that chromium contained in the passive film is associated with the disorder
in the film Fe-O and Fe-Fe bond lengths compatible with the known oxides
and hydroxides of iron have been obtained, but the uncertainties in the
bond length determination prevent any structure being put forward for the
passive film.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QC Physics
Library of Congress Subject Headings (LCSH):	Passivity (Chemistry), Coatings, Chromium-iron alloys, Corrosion and anti-corrosives, Extended X-ray absorption fine structure
Official Date:	November 1986
Dates:	Date Event November 1986 Submitted
Institution:	University of Warwick
Theses Department:	Department of Physics
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Forty, A. J.
Sponsors:	Science and Engineering Research Council (Great Britain) (SERC) ; Atomic Energy Research Establishment (Harwell, England)
Extent:	xii, 139 p.
Language:	eng

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