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Title: Hydrogen absorption properties of amorphous (Ni 0.6Nb 0.4-yTa y ) 100-x Zr x membranes

Ni based amorphous materials have great potential as hydrogen purification membranes. In the present work the melt spun (Ni 0.6Nb 0.4-yTa y) 100-xZr x with y=0, 0.1 and x=20, 30 was studied. Our result of X-ray diffraction spectra of the ribbons showed an amorphous nature of the alloys. Heating these ribbons below T < 400 °C, even in a hydrogen atmosphere (1-10 bar), the amorphous structure was retained. Furthermore, the crystallization process was characterized by differential thermal analysis and the activation energy of such process was obtained. The hydrogen absorption properties of the samples in their amorphous state were studied by the volumetric method, and the results showed that the addition of Ta did not significantly influence the absorption properties, a clear change of the hydrogen solubility was observed with the variation of the Zr content. The values of the hydrogenation enthalpy changed from ~37 kJ/mol for x=30 to ~9 kJ/mol for x=20. Our analysis of the volumetric data provides the indications about the hydrogen occupation sites during hydrogenation, suggesting that at the beginning of the absorption process the deepest energy levels are occupied, while only shallower energy levels are available at higher hydrogen content, with the available interstitial sitesmore » forming a continuum of energy levels.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [3] ;  [3] ;  [4] ;  [5] ;  [1]
  1. National Center for Research, Rome (Italy). Inst. for Complex System (CNR-ISC)
  2. National Center for Research, Rome (Italy). Inst. for Complex System (CNR-ISC); Univ. of Rome (Italy). Dept. of Physics
  3. Univ. of Nevada, Reno, NV (United States). Dept. of Chemical and Materials Engineering
  4. Univ. of Vermont, Burlington, VT (United States). Dept. of Chemistry
  5. Commonwealth Scientific and Industrial Research Organisation (CSIRO), Pullenvale (Australia). Queensland Center for Advanced Technologies (QCAT)
Publication Date:
Grant/Contract Number:
NA0002004; US DE-NA0002004
Type:
Published Article
Journal Name:
Progress in Natural Science
Additional Journal Information:
Journal Volume: 27; Journal Issue: 1; Journal ID: ISSN 1002-0071
Publisher:
Chinese Materials Research Society
Research Org:
Univ. of Nevada, Reno, NV (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Amorphous Ni based alloy ribbons; High temperature X-ray diffraction; DTA; Activation energy; Crystallization temperature; Hydrogen solubility; High temperature X-ray; diffraction; Crystallization temperature Hydrogen solubility
OSTI Identifier:
1389663
Alternate Identifier(s):
OSTI ID: 1356173; OSTI ID: 1360809