Formation of superabundant vacancies in Pd-H alloys

Yuh Fukai, Yasuyuki Ishii, Yoshihiro Goto, Kuniaki Watanabe

研究成果: Article査読

39 被引用数 (Scopus)


Temporal variation of the lattice parameter of Pd was measured under high hydrogen pressures (2-5 GPa) and temperatures (672-896 °C) by X-ray diffraction using a synchrotron radiation, and observed lattice contraction was interpreted as being due to the formation of a large number of vacancy-hydrogen (Vac-H) clusters, i.e. superabundant vacancies. Analysis of the result led to the conclusion that a major part of Vac-H clusters (amounting to approximately 10 at.%) were introduced by diffusion from the surface, after a small number of them had been formed at some internal sources. The thermal-equilibrium concentration of Vac-H clusters at high temperatures shows a saturation behavior, which indicates the presence of a maximum possible concentration (ca. 16 at.%) of the clusters. The formation energy, entropy and volume of a Vac-H cluster are found to be 0.72 eV, 7.2 k and 0.60 Ω, respectively, and the migration energy and volume are 1.20 eV and 0.49 Ω, respectively. Various other implications of the results are also discussed.

ジャーナルJournal of Alloys and Compounds
出版ステータスPublished - 2000 12月 15

ASJC Scopus subject areas

  • 材料力学
  • 機械工学
  • 金属および合金
  • 材料化学


「Formation of superabundant vacancies in Pd-H alloys」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。