Hydrogenation behavior of the solid solutions RE₄NiMg_1−xAl_x and RE_4−yNiMg_1+y with RE = Gd and Y

Samuel Couillaud (1) , Stefan Linsinger (2) , Cédric Duée (3) , Aline Rougier (3) , Bernard Chevalier (1) , Rainer Pöttgen (2) , Jean-Louis Bobet (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 Institut für Anorganische und Analytische Chemie
3 LRCS - Laboratoire réactivité et chimie des solides - UMR CNRS 7314

The solid solutions RE₄NiMg_1−xAl_x (0 < x < 0.9) and RE_4−yNiMg_1+y (0 < y < 0.5) with RE = Gd and Y were synthesized from the elements in sealed tantalum ampoules in an induction furnace. The limit of solubility was established in both cases. All the samples crystallize with the cubic Gd₄RhIn type structure, space group F-43m. The solubility is much lower in the case of Y than for Gd which is linked with steric effects. The hydrogen sorption is irreversible and the large exothermicity of the reaction can lead to the decomposition of the compounds into rare earth hydrides and metallic Ni and Mg. Nevertheless, it is shown that the Y based compounds can absorb almost 3 wt.% of hydrogen at room temperature and under moderate pressure. Furthermore, the solid solutions do not allow destabilization of the hydrides.

Mots clés: Ternary alloy systems; Crystal chemistry of intermetallics; Hydrogen storage

Domaines: Matériaux

Samuel Couillaud, Stefan Linsinger, Cédric Duée, Aline Rougier, Bernard Chevalier, et al.. Hydrogenation behavior of the solid solutions RE₄NiMg_1−xAl_x and RE_4−yNiMg_1+y with RE = Gd and Y. Intermetallics, 2010, 18 (6), pp.1115-1121. ⟨10.1016/j.intermet.2010.02.007⟩. ⟨hal-00480899⟩