Positron annihilation analysis of the atomic scale changes in oxidized Zircaloy-4 samples
Research output: Contribution to journal › Article › Scientific › peer-review
Details
Original language | English |
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Pages (from-to) | 172-180 |
Number of pages | 9 |
Journal | Journal of Nuclear Materials |
Volume | 495 |
Publication status | Published - 1 Nov 2017 |
MoE publication type | A1 Journal article-refereed |
Researchers
Research units
- Culham Science Centre
Abstract
The process of oxidation in zirconium alloys is not straightforward. It includes cyclic periods, where the oxidation rate is decelerating as a function of increasing oxide thickness. Transition to the higher oxidation rate happens approximately after every 2 μm oxide growth and each cycle is associated with a layer of oxide with little or no cracking and a similar thickness layer with a large number of micro-scale lateral cracks. This work uses positron annihilation Doppler broadening spectroscopy to investigate the development of atomic-scale defect features in the oxides on Zircaloy-4 samples exposed to alkaline water at 350 °C. Results from the Doppler broadening measurements supported by Density Functional Theory calculations indicate that complexes involving both zirconium-site and oxygen-site vacancies exist in the oxide. The implications of the vacancies in the oxide layer are considered for oxygen diffusion and the oxidation rate.
- Doppler broadening, Positron annihilation spectroscopy, Zirconium oxidation
Research areas
ID: 14874438