X-ray absorption study of electrochemicallly grown oxide films on AlCr sputtered alloys; II: In situ studies
- IBM T.J. Watson Research Center, Yorktown Heights, NY (United States). Research Div.
- Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science
The chemistry of chromium in the passive film on sputter-deposited chromium and AlCr thin films has been investigated in situ in an electrochemical cell under potential control by studying X-ray absorption near edge structure. At high potentials, Cr in the AlCr alloys was oxidized to the 6-valent state. Depending on the rate of potential increase, 6-valent chromium either dissolved from the alloy or was trapped in the passive film where it was electroactive, i.e., the valence state could be reversibly switched between the 3- and 6-valent states by changing the applied potential. The kinetics of these processes were investigated. Ex situ X-ray photoelectron spectroscopy measurements indicated that, during slow scanning at low potentials, the composition of both the surface oxide and underlying metallic layers changed. These changes resulted in a structure that was susceptible to transpassive dissolution of Cr at potentials above 0.2 V(MSE).
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 142209
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 1 Vol. 141; ISSN JESOAN; ISSN 0013-4651
- Country of Publication:
- United States
- Language:
- English
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