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Title: Non-equilibrium oxidation states of zirconium during early stages of metal oxidation

The chemical state of Zr during the initial, self-limiting stage of oxidation on single crystal zirconium (0001), with oxide thickness on the order of 1 nm, was probed by synchrotron x-ray photoelectron spectroscopy. Quantitative analysis of the Zr 3d spectrum by the spectrum reconstruction method demonstrated the formation of Zr{sup 1+}, Zr{sup 2+}, and Zr{sup 3+} as non-equilibrium oxidation states, in addition to Zr{sup 4+} in the stoichiometric ZrO{sub 2}. This finding resolves the long-debated question of whether it is possible to form any valence states between Zr{sup 0} and Zr{sup 4+} at the metal-oxide interface. The presence of local strong electric fields and the minimization of interfacial energy are assessed and demonstrated as mechanisms that can drive the formation of these non-equilibrium valence states of Zr.
Authors:
;  [1] ;  [1] ;  [2] ;  [3]
  1. Laboratory for Electrochemical Interfaces, Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States)
  2. (United States)
  3. Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
Publication Date:
OSTI Identifier:
22395696
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 10; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHEMICAL STATE; ELECTRIC FIELDS; EQUILIBRIUM; INTERFACES; MONOCRYSTALS; OXIDATION; PROBES; STOICHIOMETRY; VALENCE; X-RAY PHOTOELECTRON SPECTROSCOPY; ZIRCONIUM; ZIRCONIUM IONS; ZIRCONIUM OXIDES