Electrochemical behavior of thin anodic oxide films on Zircaloy-4: Role of the mobile defects
- C.E.A. Grenoble DTP/SECC, Grenoble (France)
- INP Grenoble/LTPCM, Saint Martin d`Heres (France)
The first stages of the electrochemical oxidation of Zircaloy-4 are investigated using simple electrochemical tests and modeling the passive film modifications occurring as a result of contact with the electrolyte. Variations in electrode potential (open-circuit conditions) or current density (potentiodynamic scans) can be simply explained by a high field (F {approximately} 10{sup 6} V/cm) assisted passive film growth. Under open-circuit conditions, this field does not vary with exposure time (in the 2 h to 48 h range). The minimum electric field for the onset of high-field behavior is also evaluated and found smaller than the theoretical value which can be explained by a variation in the concentration of mobile defects throughout the film. Measurements of the electrode potential decay after a potentiodynamic scan confirm this model, allowing interpretation of the film modification as a combination of two separate phenomena: film growth under a high electric field and point defect annihilation.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 474625
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 12 Vol. 143; ISSN JESOAN; ISSN 0013-4651
- Country of Publication:
- United States
- Language:
- English
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