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Journal of Low Temperature Physics

, Volume 134, Issue 5–6, pp 1145–1151 | Cite as

Phase Diagram of Hydrogen in Palladium

  • H. Araki
  • M. Nakamura
  • S. Harada
  • T. Obata
  • N. Mikhin
  • V. Syvokon
  • M. Kubota
Article

Abstract

Hydrogen in palladium, Pd-H(D), is an interesting system because of the highly mobile hydrogen and the presence of a phase boundary below 100 K. Experimentally, however, the nature of this transition has not been established. Historically this transition around 55 to 100 K has been thought to be an order-disorder transition. Such a transition would produce a phase boundary with anomalies at specific hydrogen concentrations corresponding to the specific ordered structures. In order to check this phase boundary we have performed a detailed study of the hydrogen concentration dependence of the specific heat of PdH x over the temperature range from below 0.5 K to above 100 K using PdH x specimens with x up to 0.8753. The measured heat capacity has been analyzed as the sum of contributions due to the lattice specific heat of Pd, the electronic specific heat of PdH x , and the excess contribution caused by hydrogenation of the specimen. The excess specific heat result shows a sharp peak which indicates a phase boundary with transition temperature T1=55 K to 85 K depending linearly on the hydrogen concentration from x=0.6572 to 0.8753. We do not observe anomalies at specific x values as would be expected for the specific ordered structures.

Keywords

Phase Diagram Heat Capacity Palladium Phase Boundary Sharp Peak 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    T. Skoskiewicz, Phys. Status Solidi a11, K123(1972).Google Scholar
  2. 2.
    D. M. Nace and G. J. Aston, J. Am. Chem. Soc. 79, 3627(1957).Google Scholar
  3. 3.
    O. Blaschko, J. Less-Common Met. 100, 307(1984).Google Scholar
  4. 4.
    P. Mitacek, Jr. and G. J. Aston, J. Am. Chem. Soc. 85, 137(1963).Google Scholar
  5. 5.
    J. K. Jacobs and F. D. Manchester, J. Phys. F 7, 23(1977).Google Scholar
  6. 6.
    C. A. Mackliet et al., J. Phys. Chem. Solid 37, 379(1976).Google Scholar
  7. 7.
    Y. Fukai, The Metal-Hydrogen System, Springer-Verlag (1993).Google Scholar
  8. 8.
    D. E. Galli and L. Reatto, J. Low Temp. Phys. 124, 197(2001).Google Scholar
  9. 9.
    H. Araki et al., Physica B 284-8, 1255(2000).Google Scholar
  10. 10.
    M. Zimmermann et al., Phys. Status Solidi a31, 511(1975).Google Scholar
  11. 11.
    G. Wolf and M. Zimmermann, Phys. Status Solidi a37, 485(1976).Google Scholar
  12. 12.
    G. Alefeld and J. Völkl eds., Hydrogen in Metals II, Springer-Verlag (1978).Google Scholar
  13. 13.
    G. J. Zimmermann, J. Less-Common Met. 49, 49(1976).Google Scholar

Copyright information

© Plenum Publishing Corporation 2004

Authors and Affiliations

  • H. Araki
    • 2
    • 3
  • M. Nakamura
    • 2
  • S. Harada
    • 2
  • T. Obata
    • 1
  • N. Mikhin
    • 1
  • V. Syvokon
    • 1
  • M. Kubota
    • 1
  1. 1.ISSP, University of TokyoKashiwa, ChibaJapan
  2. 2.Graduate School of Sci. & Tech.Niigata UniversityNiigataJapan
  3. 3.Nagaoka National College of TechnologyNagaoka, NiigataJapan

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