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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Relating the formation energies for oxygen vacancy defects to the structural properties of tungsten oxides
AU - Kerr, Ryan D.
AU - Gilbert, Mark R.
AU - Murphy, Samuel T.
PY - 2025/4/30
Y1 - 2025/4/30
N2 - Tungsten is one of the materials of choice for several commercial fusion power plant designs, in particular, for divertor targets and the first wall. In maintenance conditions or during a loss of coolant accident, tungsten is expected to reach temperatures at which it readily volatilises as tungsten trioxide, potentially distributing radioactive material and posing a hazard to personnel. The oxidation of tungsten is reported to show an orientation dependence, however, the mechanism by which it occurs is not fully understood, providing an obstacle to the development of tungsten smart alloys that display reduced oxidation. Using DFT+ U simulations, it is shown how key features of the electronic structure of the tungsten–oxygen system change as the tungsten–oxygen ratio evolves. Formation and migration barriers for oxygen in the different tungsten oxides are determined, allowing an assessment of its mobility in the phases observed during the oxidation process. Our results provide a new level of understanding of the sub-stoichiometric Magnéli phases that are observed during the oxidation of tungsten, which are perceived to be composed of WO2- and WO3-like regions.
AB - Tungsten is one of the materials of choice for several commercial fusion power plant designs, in particular, for divertor targets and the first wall. In maintenance conditions or during a loss of coolant accident, tungsten is expected to reach temperatures at which it readily volatilises as tungsten trioxide, potentially distributing radioactive material and posing a hazard to personnel. The oxidation of tungsten is reported to show an orientation dependence, however, the mechanism by which it occurs is not fully understood, providing an obstacle to the development of tungsten smart alloys that display reduced oxidation. Using DFT+ U simulations, it is shown how key features of the electronic structure of the tungsten–oxygen system change as the tungsten–oxygen ratio evolves. Formation and migration barriers for oxygen in the different tungsten oxides are determined, allowing an assessment of its mobility in the phases observed during the oxidation process. Our results provide a new level of understanding of the sub-stoichiometric Magnéli phases that are observed during the oxidation of tungsten, which are perceived to be composed of WO2- and WO3-like regions.
U2 - 10.1016/j.commatsci.2025.113781
DO - 10.1016/j.commatsci.2025.113781
M3 - Journal article
VL - 252
JO - Computational Materials Science
JF - Computational Materials Science
SN - 0927-0256
M1 - 113781
ER -