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Title: UO[subscript 2] Oxidative Corrosion by Nonclassical Diffusion

Authors:
; ; ; ; ; ;  [1];  [2];  [2]
  1. UC
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
DOE - BASIC ENERGY SCIENCESNSF
OSTI Identifier:
1186917
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 114; Journal Issue: 24
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Stubbs, Joanne E., Chaka, Anne M., Ilton, Eugene S., Biwer, Craig A., Engelhard, Mark H., Bargar, John R., Eng, Peter J., SSRL), and PNNL). UO[subscript 2] Oxidative Corrosion by Nonclassical Diffusion. United States: N. p., 2016. Web. doi:10.1103/PhysRevLett.114.246103.
Stubbs, Joanne E., Chaka, Anne M., Ilton, Eugene S., Biwer, Craig A., Engelhard, Mark H., Bargar, John R., Eng, Peter J., SSRL), & PNNL). UO[subscript 2] Oxidative Corrosion by Nonclassical Diffusion. United States. doi:10.1103/PhysRevLett.114.246103.
Stubbs, Joanne E., Chaka, Anne M., Ilton, Eugene S., Biwer, Craig A., Engelhard, Mark H., Bargar, John R., Eng, Peter J., SSRL), and PNNL). 2016. "UO[subscript 2] Oxidative Corrosion by Nonclassical Diffusion". United States. doi:10.1103/PhysRevLett.114.246103.
@article{osti_1186917,
title = {UO[subscript 2] Oxidative Corrosion by Nonclassical Diffusion},
author = {Stubbs, Joanne E. and Chaka, Anne M. and Ilton, Eugene S. and Biwer, Craig A. and Engelhard, Mark H. and Bargar, John R. and Eng, Peter J. and SSRL) and PNNL)},
abstractNote = {},
doi = {10.1103/PhysRevLett.114.246103},
journal = {Physical Review Letters},
number = 24,
volume = 114,
place = {United States},
year = 2016,
month = 6
}
  • Uranium oxide is central to every stage of the nuclear fuel cycle, from mining through fuel fabrication and use, to waste disposal and environmental cleanup. Its chemical and mechanical stability are intricately linked to the concentration of interstitial O atoms within the structure and the oxidation state of U. We have previously shown that during corrosion of the UO2 (111) surface under either 1 atm O2 gas or oxygenated water at room temperature, oxygen interstitials diffuse into the substrate to form a superlattice with three-layer periodicity. In the current study, we present results from surface x-ray scattering that reveal themore » structure of the oxygen diffusion profile beneath the (001) surface. The first few layers below the surface oscillate strongly in their surface-normal lattice parameters, suggesting preferential interstitial occupation of every other layer below the surface, which is geometrically consistent with the interstitial network that forms below the oxidized (111) surface. Deeper layers are heavily contracted and indicate that the oxidation front penetrates ~52 Å below the (001) surface after 21 days of dry O2 gas exposure at ambient pressure and temperature. X-ray photoelectron spectroscopy indicates U is present as U(IV), U(V), and U(VI).« less
  • Reactions of carboxylic acids with lead play an important role in the atmospheric corrosion of lead and lead-tin alloys. This is of particular concern for the preservation of lead-based cultural objects, including historic lead-tin alloy organ pipes. Two initial corrosion products, Pb{sub 3}O{sub 2}(CH{sub 3}COO){sub 2} {center_dot} 0.5H{sub 2}O (1) and Pb{sub 2}O(HCOO){sub 2} (2), had been identified through powder diffraction fingerprints in the Powder Diffraction File, but their structures had never been determined. We have crystallized both compounds using hydrothermal solution conditions, and structures were determined using laboratory and synchrotron single-crystal X-ray diffraction data. Compound 1 crystallizes in P{submore » t}, and 2 in Cccm. These compounds may be viewed as inorganic-organic networks containing single and double chains of edge-sharing Pb{sub 4}O tetrahedra and have structural similarities to inorganic basic lead compounds. Bond valence sum analysis has been applied to the hemidirected lead coordination environments in each compound. Atmospheric exposure experiments contribute to understanding of the potential for conversion of these short-term corrosion products to hydrocerussite, Pb{sub 3}(CO{sub 3}){sub 2}(OH){sub 2}, previously identified as a long-term corrosion product on lead-rich objects. Each compound was also characterized by elemental analysis, thermogravimetric analysis and differential scanning calorimetry (TGA-DSC), and Raman spectroscopy.« less