The hydriding kinetics of bulk metallic holmium under 1bar H2 and below 570K

Bloch, J.

doi:10.1016/j.jallcom.2007.10.145

Cited by 3 publications

(1 citation statement)

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“…Despite a number of kinetic studies on hydrogenation of rare earth metals and decomposition of their hydrides has been published so far, these works containing only a few studies of the hydrides of "heavy" RE, including absorption of hydrogen by Ho [10] and hydrogen desorption from erbium hydride [11], were focused on the investigations of the kinetic properties in the metal hydride systems containing "heavy" RE while earlier performed studies of the desorption properties of the rare earth hydrides are limited to Y and RE ¼ La, Ce, Pr, Nd, Sm, Gd, Tb and Er [1,5]. The Thermal Desorption Spectroscopy (TDS) study together with characterization of the kinetics of metal-hydrogen interactions allows identifying possible mechanisms and ratecontrolling steps of hydrogen desorption [12] but unfortunately such studies have not been performed for the hydrides of heavy rare earth metals yet.…”

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confidence: 99%

Thermal desorption spectroscopy studies of hydrogen desorption from rare earth metal trihydrides REH3 (RE=Dy, Ho, Er)

Suwarno

Lototskyy

Yartys

2020

Journal of Alloys and Compounds

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Rare earth (RE) metals form two stoichiometric hydrides, REH 2 and REH 3 , and for the yttrium group of RE transformation of a FCC (REH 2) into an HCP (REH 3) lattice takes place during the second step of hydrogenation REH 2 þ ½ H 2 / REH 3. Earlier studies of the hydrogen desorption properties of the rare earth hydrides were limited to Y and RE ¼ La, Ce, Pr, Nd, Sm, Gd, Tb and Er. The present work is focused on the studies of the kinetics and mechanism of hydrogen desorption from trihydrides of heavy rare earths, DyH 3 , HoH 3, and ErH 3. The Thermal Desorption Spectroscopy (TDS) studies were performed at pressures below 1 Â 10 À5 mbar during linear heating from room temperature to 1173 K at different heating rates ranging from 1 to 5.5 K/min. Hydrogen desorption traces show the presence of two main events with the low-temperature peak appearing below 573 K, while the second peak is positioned at 1083e1159 K, with the peak temperatures gradually increasing following the rise of the heating rate. Fitting of the peak temperatures in the TDS spectra using the Kissinger method yielded activation energies of hydrogen desorption for both hydrogen desorption events. For DyH 3 and ErH 3 , the shapes of the TDS spectra appear to be well described by a phase-stuctural transformation following a model of nucleation and growth, while for HoH 3 the dehydrogenation mechanism includes a phase boundary reaction. This applied model of phase-structural transformations shows differences in dimensionality and rate-limiting steps as related to the studied compound and the desorption events, REH 3 / REH 2 or REH 2 / RE.

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