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The initial interactions of beryllium with O2and H2O vapor at elevated temperatures

Authors
Journal
Surface Science
0039-6028
Publisher
Elsevier
Publication Date
Volume
601
Issue
5
Identifiers
DOI: 10.1016/j.susc.2006.12.060
Keywords
  • Auger Electron Spectroscopy
  • Ion Scattering Spectroscopy
  • Adsorption Kinetics
  • Oxidation
  • Beryllium

Abstract

Abstract In the 310–790 K temperature range, the mechanism of initial oxidation by O 2 is oxide island nucleation and growth. At the lower temperature range, oxygen is first chemisorbed and the oxide nucleates at coverage of ∼0.2. Increasing the temperature causes the oxide islands to nucleate at lower coverage and at 700 K and above, the oxide nucleates without any significant stage of chemisorbed oxygen. The temperature dependence shows that while the dissociation stage is not activated, the oxide nucleation and growth are thermally activated. Also, opposite to O 2 adsorption, the initial H 2O adsorption and oxidation rate was found to decrease with temperature. Opposite to the oxygen case, upon exposure to water vapor there is no noticeable stage of chemisorbed oxygen (or OH) and oxide is directly nucleated. Only after oxide coalescence, this tendency changes and the oxidation rate is increased with temperature.

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