Studying the Interaction of LaNi5 Intermetallic Alloy with Oxygen by SIMS

Litvinov, V. A.; Okseniuk, I.I.; Shevchenko, D.I.; Bobkov, V. V.

doi:10.1134/s102745102006035x

Cited by 3 publications

(3 citation statements)

References 25 publications

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“…In the following section we present the results of the SIMS studies of the surface monolayers chemical composition of the intermetallic alloy LaNi 5 in the process of its interaction with oxygen [60,61].…”

Section: Sims Investigation Of Chemical Composition Of the Compounds ...mentioning

confidence: 99%

The Role of Surface in Hydride Formation Processes

Litvinov,

Okseniuk,

Shevchenko

et al. 2023

East Eur. J. Phys.

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Several LaNi5-based hydrogen storage alloys were studied using secondary ion mass spectrometry (SIMS) technique. Ar+ ions with the energy of 10 - 18 keV were used as primary ions. The study of the initial stages of the processes of LaNi5-based alloys interaction with hydrogen under the experimental conditions showed that on the areas of clean surface, hydrogen formed chemical compounds with the both of the main components of the alloy: nickel and lanthanum. As hydrogen accumulates on the surface and in the near-surface region, a hydrogen-containing structure is formed, which is characterized by a certain stoichiometric ratio of components. Nickel in this structure has strong chemical bonds with two hydrogen atoms, and lanthanum – with two or more hydrogen atoms. Along with such compounds, some structures with lower hydrogen content are also formed. The formed hydrogen-containing structure includes both main alloy components, La and Ni for all the studied samples, even though only lanthanum is generally accepted to be the hydride-forming element in such alloys. The SIMS studies of the chemical composition of the surface monolayers of the intermetallic alloy LaNi5, in the process of its interaction with oxygen, showed the following. As a result of the oxygen interaction with the alloy, a complex chemical structure including oxygen, lanthanum and nickel is formed on the surface and in the near-surface region of LaNi5. Oxygen in such a structure, similarly to hydrogen, forms strong chemical bonds with both components of the alloy. This is indicated by the presence in the mass spectra of a large set of oxygen-containing emissions of positive and negative secondary ions with lanthanum and nickel, as well as oxygen-containing lanthanum-nickel cluster secondary ions. The formed oxide compounds have a three-dimensional structure and occupy tens of monolayers. Oxygen poisoning of the surface of the hydride-forming alloy LaNi5 can occur regardless of whether the surface of the alloy was clean from the very beginning or it was covered with a layer of hydrogen-containing chemical compounds.

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Section: Sims Investigation Of Chemical Composition Of the Compounds ...mentioning

confidence: 99%

The Role of Surface in Hydride Formation Processes

Litvinov,

Okseniuk,

Shevchenko

et al. 2023

East Eur. J. Phys.

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“…A possible explanation of this decrease may be the presence of surface oxide. It is well known that, on the surface of LaNi 5 , there is segregation due to a difference in the surface energy of the alloy components [28][29][30][31]. This results in a coating of La 2 O 3 or La(OH) 3 with a thin surface layer of NiO.…”

Section: First Hydrogenation and Dehydrogenationmentioning

confidence: 99%

“…Under hydrogen, the NiO is reduced, and nickel then acts as an active cluster for the decomposition of H 2 molecules. Litvinov et al estimated the thickness of oxide to be of the order of one dozen monolayers [31]. However, the oxide was formed under controlled mild conditions (room temperature (3.3 × 10 −4 Pa of oxygen for 45 s).…”

Section: First Hydrogenation and Dehydrogenationmentioning

confidence: 99%

Effect of HPT on the First Hydrogenation of LaNi5 Metal Hydride

et al. 2021

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This paper reports the effect of high-pressure torsion (HPT) on the first hydrogenation of LaNi5. We found that, for loose powder, reduction of particle size has an effect of increasing the incubation time and decreasing the hydrogen capacity. A higher amount of HPT turns only marginally reduce the incubation time but has no effect on hydrogen capacity. In all cases, the first dehydrogenation and subsequent hydrogenation have the same kinetics, irrespective of the particle size or number of HPT turns. Therefore, for LaNi5, HPT has a beneficial effect only for the first hydrogenation.

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SIMS studies of hydrogen interaction with the TiFe alloy surface: hydrogen influence on secondary ion yields

Okseniuk

Shevchenko

2022

Surface Science

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Studying the Interaction of LaNi5 Intermetallic Alloy with Oxygen by SIMS

Cited by 3 publications

References 25 publications

The Role of Surface in Hydride Formation Processes

The Role of Surface in Hydride Formation Processes

Effect of HPT on the First Hydrogenation of LaNi5 Metal Hydride

SIMS studies of hydrogen interaction with the TiFe alloy surface: hydrogen influence on secondary ion yields

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