Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5450425 | Progress in Natural Science: Materials International | 2017 | 6 Pages |
Abstract
Ni based amorphous materials have great potential as hydrogen purification membranes. In the present work the melt spun (Ni0.6Nb0.4âyTay)100âxZrx with y=0, 0.1 and x=20, 30 was studied. The 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 (1â10 bar), the amorphous structure was retained. 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. The 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 sites forming a continuum of energy levels.
Keywords
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Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
O. Palumbo, F. Trequattrini, N. Pal, M. Hulyalkar, S. Sarker, D. Chandra, T. Flanagan, M. Dolan, A. Paolone,