PL EN


Preferences help
enabled [disable] Abstract
Number of results
2008 | 63 | 271-286
Article title

The interaction of water vapor and hydrogen water mixtures with a polycrystalline uranium surface

Content
Title variants
Languages of publication
EN
Abstracts
EN
The initial room-temperature interactions of water vapor with polycrystalline bulk annealed uranium surfaces were studied by combined measurements utilizing Direct Recoil Spectrometry (DRS) and X-ray Photoelectron Spectroscopy (XPS). It was found that the water goes through a complete dissociation into oxidic oxygen and two neutral H atoms throughout the whole exposure range. The process proceeds by two consecutive stages: (i) below about 80% monolayer coverage, the dissociation products chemisorb mainly on the remaining non-reacted metallic surface by a simple Langmuir-type process; (ii) Between about 80% and full coverage, three dimensional oxide islands (that start to form at 50-60% coverage) cover most of the surface and full dissociation continues on top of them, with part of the hydrogen staying on top of the oxide. It was also found that traces of about 2% water vapor are sufficient to inhibit hydrogen dissociation and chemisorption on uranium surfaces, under low pressure exposures, at room temperature. The efficiency of the inhibition increases with temperature in the range of 200 - 400 K. The inhibition effect is also influenced by the extent of residual strain of the sample, with increasing inhibition efficiencies exhibited by a less strained surface. O2, in contrast to H2O, is not an inhibitor to surface adsorption and dissociation of hydrogen. Three types of mechanisms are discussed in order to account for the above inhibition effect of water. It is concluded that the most probable mechanism involves the reversible adsorption of water molecules on hydrogen dissociation sites causing their "blocking".
Keywords
Publisher
Year
Volume
63
Pages
271-286
Physical description
Dates
published
1 - 1 - 2008
online
5 - 3 - 2010
References
  • P. A. Thiel, T. E. Madey, Surf. Sci. Rep. 7, 211 (1987)
  • M. A. Henderson, Surf. Sci. Rep. 46 1, (2002).
  • K. Winer, C. A. Colmenares, R. L. Smith, F. Wooten, Surf. Sci. 183 349, (1987).
  • M. Balooch, A. V. Hamza, J. Nucl. Mater. 230, 259, (1996).
  • W. L. Manner, J. A. Lloyd, M. T. Paffett, J. Nucl. Mater., 275, 37 (1999).
  • M. N. Hedhili, B. V. Yashinskiy, T. E. Madey, Surf. Sci., 445, 512 (2000).
  • M. T. Paffett, D. Kelly, S. A. Joyce, J. Morris, K. Veirs, J. Nucl. Mater., 332, 45 (2003).
  • J. Stultz, M. T. Paffett, S. A. Joyce, J. Chem. Phys. B, 108, 2362 (2004).
  • S. D. Senanayake, H. Idriss, Surf. Sci., 563, 135 (2004).
  • E. Tiferet, M. H. Mintz, S. Zalkind, I. Jacob and N. Shamir, J. Alloys Comp., 444-445, 177 (2007).
  • J. W. Rabalais, CRC Crit. Rev. Solid State Mater. Sci., 14, 318 (1988).
  • M. S. Hammond, J. A. Schultz, A. R. Krauss, J. Vac. Sci. Technol. A, 13 1136 (1995).
  • M. H. Mintz, J. A. Schultz, J. Less-Common Met., 103, 349 (1984).
  • E. Swissa, I. Jacob, U. Atzmony, N. Shamir, M. H. Mintz, Surf. Sci., 223, 607 (1989).
  • M. H. Mintz and N. Shamir, Appl. Surf. Sci., 252, 633 (2005).
  • N. Shamir, E. Tiferet, S. Zalkind, M. H. Mintz, Surface Sci., 600, 657 (2006).
  • E. Tiferet, S. Zalkind, M. H. Mintz, I. Jacob and N. Shamir, Surf. Sci., 601, 936 (2007).
  • E. Tiferet, M. H. Mintz, I. Jacob and N. Shamir, Surf. Sci., 601, 4925 (2007).
  • D.A. King and M.G. Wells, Proc. R. Soc. Lond., A 339, 245 (1975).
Document Type
Publication order reference
YADDA identifier
bwmeta1.element.-psjd-doi-10_2478_v10063-009-0015-1
Identifiers
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.