The vibrational excitations and the position of hydrogen in nanocrystalline palladium
U Stuhr; H Wipf; T J Udovic; J Weissmuller; H Gleiter; U Stuhr; Inst. fur Festkorperphys., Tech. Hochschule Darmstadt, Germany; H Wipf; Inst. fur Festkorperphys., Tech. Hochschule Darmstadt, Germany; T J Udovic; Inst. fur Festkorperphys., Tech. Hochschule Darmstadt, Germany; J Weissmuller; Inst. fur Festkorperphys., Tech. Hochschule Darmstadt, Germany; H Gleiter; Inst. fur Festkorperphys., Tech. Hochschule Darmstadt, Germany
Журнал:
Journal of Physics: Condensed Matter
Дата:
1995-01-09
Аннотация:
The vibrational excitations and the position of hydrogen in nanocrystalline palladium were investigated by means of inelastic neutron-scattering and H solubility measurements. The study focuses on the H concentration regime (<or=4.8 at.% H) where, at room temperature, no precipitation of the H in a hydride phase ( beta -phase) was observed. In this concentration regime, the solubility measurements show an enhanced H solubility relative to coarse-grained Pd. The neutron-scattering experiments show that this additional H is incorporated in the grain boundaries and at the surface of the grains. Surface modes of H at approximately 90 and 120 meV were identified. Compared to coarse-grained Pd, no change in the H solubility was found for the crystal lattice of the nanosized grains.
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