title: UO(2) Oxidative Corrosion by Nonclassical Diffusion.
abstract: Using x-ray scattering, spectroscopy, and density-functional theory, we determine the structure of the oxidation front when a UO(2) (111) surface is exposed to oxygen at ambient conditions. In contrast to classical diffusion and previously reported bulk UO(2+x) structures, we find oxygen interstitials order into a nanoscale superlattice with three-layer periodicity and uranium in three oxidation states: IV, V, and VI. This oscillatory diffusion profile is driven by the nature of the electron transfer process, and has implications for understanding the initial stages of oxidative corrosion in materials at the atomistic level.
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60439, USA.
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Stubbs
authors.affiliation: Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Chaka
authors.affiliation: Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Eugene S
authors.initials: ES
authors.lastname: Ilton
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60439, USA.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Biwer
authors.affiliation: EMSL, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Engelhard
authors.affiliation: Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Bargar
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60439, USA.|James Franck Institute, University of Chicago, Chicago, Illinois 60439, USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Eng
mesh_terms: D003343:Corrosion; D004058:Diffusion; D008956:Models, Chemical; D010084:Oxidation-Reduction; D017974:Uranium Compounds / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D017974:Uranium Compounds; C012597:uranium dioxide