Hydrogen absorbing characteristics of nano-structured palladium via bulk mechanical alloying

Tatsuhiko Aizawa, Toshiro Kuji, Hiroaki Nakano

Research output: Contribution to journalArticlepeer-review


Nano-structured functional materials are expected to have superior properties to the coarse-grained, bulk materials. In the present paper, pure palladium is refined to nano-sized state to investigate the hydrogen absorption and desorption behavior. Using the bulk mechanical alloying, the palladium platelets can be successfully refined to nano-sized grains with the order to 10 nm. In comparison of pressure composition isotherms between nano-sized and bulk palladium, the phase boundary of the Pd-H miscibility gap is significantly narrower for nano-Pd. While the hydrogen solubility at α/(α + β) phase boundary is much increased, that at β/(α + β) phase boundary is drastically reduced by nano-structuring. This might be because of the broadening of the site energy distribution, induced by the intrinsic strains constraining the nano-grains. The broadening mechanism of site energy distribution has direct influence on the hydrogen absorption and desorption processes. The Curie temperature for hydrogen adsorption and desorption is drastically reduced by 135 K through the nanostructuring. The above precise discussion helps us to make nanostructured material design in the hydrogen storage alloys and compounds.

Original languageEnglish
Pages (from-to)960-965
Number of pages6
JournalFuntai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
Issue number10
Publication statusPublished - 2001 Oct


  • Bulk mechanical alloying
  • Hydrogen absorption behavior
  • Hydrogen desorption behavior
  • Hydrogen storage properties
  • Intrinsic strains
  • Nano-structuring
  • Palladium
  • Site energy distribution

ASJC Scopus subject areas

  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Metals and Alloys
  • Materials Chemistry


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