Abstract
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(NO3)3 solution at constant current results in a Cr3+ oxide (hydroxide) film. Deposition from a 0.01 M K2CrO4 solution produces a film which is predominantly Cr3+ but with some Cr6+. This material is air-sensitive and the ratio of Cr6+ to Cr3+ increases with time of exposure to ambient. Cathodic codeposition of Cr3+ with nickel hydroxide from Cr(NO3)3 solution results in a film with chromium in the 3+ oxidation state. On the other hand, cathodic codeposition from a Cr6+ solution of K2CrO4 with nickel hydroxide leads to a film containing Cr6+.
| Original language | English |
|---|---|
| Pages (from-to) | 2941-2945 |
| Number of pages | 5 |
| Journal | Electrochimica Acta |
| Volume | 44 |
| Issue number | 17 |
| DOIs | |
| State | Published - Apr 15 1999 |
Funding
Financial support of this research was provided by the US Department of Energy (DOE), Office of Environmental Management and Office of Energy Research under contract No. W-31-109-ENG-38. We are grateful to Dr. Joseph Woicik for providing beamtime and assistance in carrying out some of the measurements at the National Institute of Standards and Technology's beamline X23-A2. We acknowledge the US DOE for its role in the development and operation of the National Synchrotron Light Source at Brookhaven National Laboratory.