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Defect accumulation in swift heavy ion-irradiated CeO2 and ThO2

Palomares, Raul I. and Shamblin, Jacob and Tracy, Cameron L. and Neuefeind, Joerg and Ewing, Rodney C. and Trautmann, Christina and Lang, Maik (2017):
Defect accumulation in swift heavy ion-irradiated CeO2 and ThO2.
In: Journal of Materials Chemistry A, Royal Society of Chemistry, pp. 12193-12201, 5, (24), ISSN 2050-7488,
DOI: 10.1039/C7TA02640D,
[Online-Edition: https://doi.org/10.1039/C7TA02640D],
[Article]

Abstract

Neutron total scattering was used to investigate defect accumulation mechanisms in CeO2 and ThO2 irradiated with 2.2 GeV Au ions. Pair distribution function (PDF) analysis was applied to characterize the local structural evolution and irradiation-induced defects as a function of irradiation fluence. CeO2 exhibits a greater amount of disorder than ThO2 under the same irradiation conditions. The local structures of the two materials evolve differently as a function of ion fluence, even if similar defects are produced. The PDF analysis indicates that oxygen dimer and/or peroxide defects with 〈O–O〉 distances of ∼1.45 Å are formed in CeO2, while irradiation-induced defects in ThO2 result in a change in the mean O–Th–O bond angle and a distortion of local ThO8 polyhedra. Understanding how bound oxygen defects, such as peroxide, affect bulk oxygen transport in CeO2 will aid in better predicting and improving properties of fluorite structure materials for fast ion conductor applications.

Item Type: Article
Erschienen: 2017
Creators: Palomares, Raul I. and Shamblin, Jacob and Tracy, Cameron L. and Neuefeind, Joerg and Ewing, Rodney C. and Trautmann, Christina and Lang, Maik
Title: Defect accumulation in swift heavy ion-irradiated CeO2 and ThO2
Language: English
Abstract:

Neutron total scattering was used to investigate defect accumulation mechanisms in CeO2 and ThO2 irradiated with 2.2 GeV Au ions. Pair distribution function (PDF) analysis was applied to characterize the local structural evolution and irradiation-induced defects as a function of irradiation fluence. CeO2 exhibits a greater amount of disorder than ThO2 under the same irradiation conditions. The local structures of the two materials evolve differently as a function of ion fluence, even if similar defects are produced. The PDF analysis indicates that oxygen dimer and/or peroxide defects with 〈O–O〉 distances of ∼1.45 Å are formed in CeO2, while irradiation-induced defects in ThO2 result in a change in the mean O–Th–O bond angle and a distortion of local ThO8 polyhedra. Understanding how bound oxygen defects, such as peroxide, affect bulk oxygen transport in CeO2 will aid in better predicting and improving properties of fluorite structure materials for fast ion conductor applications.

Journal or Publication Title: Journal of Materials Chemistry A
Volume: 5
Number: 24
Publisher: Royal Society of Chemistry
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Ion-Beam-Modified Materials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 29 Dec 2017 12:16
DOI: 10.1039/C7TA02640D
Official URL: https://doi.org/10.1039/C7TA02640D
Funders: This research is funded by the Office of Basic Energy Sciences of the U.S. Department of Energy as part of the Materials Science of Actinides Energy Frontier Research Center (DE-SC0001089)., The research at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy., HPCAT operations are supported by DOE-NNSA under Award No. DE-NA0001974 and DOE-BES under Award No. De-FG02-99ER45775, with partial instrumentation funding by NSF., R.I.P.gratefully acknowledges support from the U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA) through the Carnegie DOE Alliance Center (CDAC) under grant number DE-NA-0002006.
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