X-ray absorption study of electrochemicallly grown oxide films on AlCr sputtered alloys; II: In situ studies

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.2054714· OSTI ID:142209

Frankel, G S; Schrott, A G; Jahnes, C V; Russak, M A ^[1]; Davenport, A J; Isaacs, H S ^[2]

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1. IBM T.J. Watson Research Center, Yorktown Heights, NY (United States). Research Div.
2. 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

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CHEMICAL COMPOSITION
CHROMIUM ALLOYS
CHROMIUM OXIDES
CORROSION RESISTANCE
EXPERIMENTAL DATA
PASSIVATION
PROTECTIVE COATINGS
VALENCE