Structural peculiarities in the β phase of the La0.75Ce0.25Ni4.8Al0.2 deuterides

In this contribution the structural, magnetic and sorption properties of the novel La0.75Ce0.25Ni4.8Al0.2 alloy and its deuterides are discussed. The collected data indicate good stability of the alloy during the cycle-life and thermal treatment tests. Particularly, the desorption pressure is almost...

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Bibliographic Details
Published in:Journal of alloys and compounds 2019-06, Vol.788, p.533-540
Main Authors: Czub, J., Jamka, W., Przewoźnik, J., Zarzecka, A., Hoser, A., Wallacher, D., Grimm, N., Gondek, Ł.
Format: Article
Language:English
Subjects:
Beta phase
Cerium
Composition
Deuterides
Deuterium
Heat treatment
Hydrides
Magnetic ordering
Magnetic properties
Magnetism
Neutron diffraction
Neutrons
Occupation
Solid solutions
Sorption
Sorption properties
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Summary:In this contribution the structural, magnetic and sorption properties of the novel La0.75Ce0.25Ni4.8Al0.2 alloy and its deuterides are discussed. The collected data indicate good stability of the alloy during the cycle-life and thermal treatment tests. Particularly, the desorption pressure is almost constant versus the cycle number. The results of the in-situ neutron diffraction studies show the unusual behaviour of the deuterium rich β phase. Unexpectedly, the β phase belongs to the same P6/mmm space group as the hydrogen poor α phase. Moreover, the β phase behaves like a solid solution on the plateau of the pressure-composition-temperature (PCT) curve. The deuterium sites and their occupations in both α and β phases are determined from the neutron diffraction data, giving the first-hand insight into the mechanism of the PCT hysteresis. As far as the magnetic properties are concerned, cerium is trivalent in the investigated alloy. However, no magnetic ordering down to 3 K is observed. It can be concluded that the sorption properties of the crystal depend on the cerium valence, what distinguishes the alloy from the other compositions. •The novel La0.75Ce0.25Ni4.8Al0.2 alloy does not show expected distortion during deuteration.•The PCT hysteresis is related to the non-homogeneous release of deuterium from different sites.•The hydrogen poor (α) and rich (β) phases behave as solid solutions.•Magnetic properties are a good measure of the material degradation during cycle life studies.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2019.02.259