1. Hydrogen interactions with intrinsic point defects and hydrogen diffusion in tungsten doped Al2O3.
- Author
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Long, Qian, Ding, Rui, Chen, Yuanzheng, Wang, Hongyan, and Guo, Chunsheng
- Subjects
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HYDROGEN isotopes , *DIFFUSION barriers , *KIRKENDALL effect , *POINT defects , *HYDROGEN , *TUNGSTEN - Abstract
In light of the extensive use of tungsten (W) in fusion experimental devices and the importance of hydrogen isotopes permeation, based on the first principle approaches we study the effects of W doping on the formation energies of intrinsic point defects, hydrogen interactions with such defects, and hydrogen diffusion in bulk of α-Al 2 O 3. Our investigation demonstrated that W doping enhances the formation of oxygen and aluminum vacancies (Vo and V Al) in α-Al 2 O 3. In W doping α-Al 2 O 3 , hydrogen primarily exists in the form of Ho− (hydrogenation of the bulk V O 3−) and Hi− (H interstitial) defects, while it hardly occupies V Al. Hydrogen is firmly trapped by Vo with a formation energy −3.35eV, and Hi− diffusion become extremely challenging because W doping significantly raises the Hi− diffusion barrier to 4.44 eV. Our findings indicate that W doping is beneficial for hydrogen permeation resistance in α-Al 2 O 3. • W doping in α-Al 2 O 3 promotes oxygen and aluminum vacancies (Vo and V Al). • Hydrogen is firmly trapped by Vo (formation energy: −3.35eV) and rarely occupies V Al. • Hydrogen exists as Hi− (H interstitial) and Ho− (hydrogenation of bulk V O 3−). • W doping increases the migration barrier for Hi− to 4.44 eV, significantly limiting hydrogen permeation in α-Al 2 O 3. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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