Hydrogen desorption properties of mechanically alloyed MgH2 composite materials

Citation
H. Reule et al., Hydrogen desorption properties of mechanically alloyed MgH2 composite materials, J ALLOY COM, 305(1-2), 2000, pp. 246-252
Citations number
16
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF ALLOYS AND COMPOUNDS
ISSN journal
09258388 → ACNP
Volume
305
Issue
1-2
Year of publication
2000
Pages
246 - 252
Database
ISI
SICI code
0925-8388(20000606)305:1-2<246:HDPOMA>2.0.ZU;2-6
Abstract
Composite H storage materials were produced by mechanical alloying of MgH2 with metallic additives La(Ni0.7Fe0.3)(5), Pd3Fe and (Fe0.8Mn0.2)Ti and wit h the non-metallic additive Si. The H desorption properties of these alloys were investigated by thermal desorption spectroscopy. The desorption spect ra yielded maximum H desorption rates at about 500 K for MgH2 + La(Ni0.7Fe0 .3)(5), between 510 K and 560 K for MgH2 + Pd3Fe and at about 570 K for MgH 2 + (Fe0.8Mn0.2)Ti, compared to a maximum at about 720 K for pure MgH2 powd er. These results showed that composite materials with metallic additives r eveal enhanced desorption kinetics. In contrast, no shift of the desorption maximum to lower temperatures was obtained by mechanically alloying MgH2 Si, Scanning electron microscopy investigations showed similar microstruct ures for all composite materials, with MgH2 covering the additive particles like a thin film of irregular thickness. Owing to these results, a model f or the H desorption process was developed with a catalytic process at the M gH2-additive interface praying a major role. (C) 2000 Elsevier Science S.A. All rights reserved.