An x-ray absorption near-edge spectroscopy study of the oxidation state of chromium in electrodeposited oxide films.

Journal Article · Fri Jan 01 04:00:00 EST 1999 · Electrochim. Acta

DOI:https://doi.org/10.1016/S0013-4686(99)00012-2· OSTI ID:938367

Balasubramanian, M; Melendres, C A

The oxidation state of chromium incorporated into simulated corrosion films of nickel has been investigated using the technique of 'in situ' X-ray Absorption Near-Edge Spectroscopy (XANES). The films were prepared by electrochemical deposition of the appropriate oxide (hydroxide) onto a graphite substrate. Cathodic deposition from a 0.01 M Cr(NO{sub 3}){sub 3} solution at constant current results in a Cr{sup 3+} oxide (hydroxide) film. Deposition from a 0.01 M K{sub 2}CrO{sub 4} solution produces a film which is predominantly Cr{sup 3+} but with some Cr{sup 6+}. This material is air-sensitive and the ratio of Cr{sup 6+} to Cr{sup 3+} increases with time of exposure to ambient. Cathodic codeposition of Cr{sup 3+} with nickel hydroxide from Cr(NO{sub 3}){sub 3} solution results in a film with chromium in the 3+ oxidation state. On the other hand, cathodic codeposition from a Cr{sup 6+} solution of K{sub 2}CrO{sub 4} with nickel hydroxide leads to a film containing Cr{sup 6+}.

• Research Organization: Argonne National Laboratory (ANL)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 938367
• Report Number(s): ANL/CMT/JA-29772
• Journal Information: Electrochim. Acta, Journal Name: Electrochim. Acta Journal Issue: 1999 Vol. 44; ISSN 0013-4686; ISSN ELCAAV
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM
CHROMIUM OXIDES
COPROCESSING
ELECTRODEPOSITION
NICKEL
VALENCE