The Role of Surface in Hydride Formation Processes
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...
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| Format: | Article |
| Language: | English |
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V.N. Karazin Kharkiv National University Publishing
2023-09-01
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| Series: | East European Journal of Physics |
| Subjects: | |
| Online Access: | https://periodicals.karazin.ua/eejp/article/view/22116 |
| _version_ | 1797689013521350656 |
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| author | Viktor O. Litvinov Ivan I. Okseniuk Dmytro I. Shevchenko Valentyn V. Bobkov |
| author_facet | Viktor O. Litvinov Ivan I. Okseniuk Dmytro I. Shevchenko Valentyn V. Bobkov |
| author_sort | Viktor O. Litvinov |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-12T01:38:47Z |
| format | Article |
| id | doaj.art-0a569c3e4b2649d68561c93583a04c4a |
| institution | Directory Open Access Journal |
| issn | 2312-4334 2312-4539 |
| language | English |
| last_indexed | 2024-03-12T01:38:47Z |
| publishDate | 2023-09-01 |
| publisher | V.N. Karazin Kharkiv National University Publishing |
| record_format | Article |
| series | East European Journal of Physics |
| spelling | doaj.art-0a569c3e4b2649d68561c93583a04c4a2023-09-10T16:51:57ZengV.N. Karazin Kharkiv National University PublishingEast European Journal of Physics2312-43342312-45392023-09-013104210.26565/2312-4334-2023-3-0122116The Role of Surface in Hydride Formation ProcessesViktor O. Litvinov0Ivan I. Okseniuk1Dmytro I. Shevchenko2Valentyn V. Bobkov3V.N. Karazin Kharkiv National University, Kharkiv, UkraineV.N. Karazin Kharkiv National University, Kharkiv, UkraineV.N. Karazin Kharkiv National University, Kharkiv, UkraineV.N. Karazin Kharkiv National University, Kharkiv, UkraineSeveral 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.https://periodicals.karazin.ua/eejp/article/view/22116simssurfaceintermetallic alloylanthanum alloylani5hydrogenmetal hydrideoxygenoxides |
| spellingShingle | Viktor O. Litvinov Ivan I. Okseniuk Dmytro I. Shevchenko Valentyn V. Bobkov The Role of Surface in Hydride Formation Processes East European Journal of Physics sims surface intermetallic alloy lanthanum alloy lani5 hydrogen metal hydride oxygen oxides |
| title | The Role of Surface in Hydride Formation Processes |
| title_full | The Role of Surface in Hydride Formation Processes |
| title_fullStr | The Role of Surface in Hydride Formation Processes |
| title_full_unstemmed | The Role of Surface in Hydride Formation Processes |
| title_short | The Role of Surface in Hydride Formation Processes |
| title_sort | role of surface in hydride formation processes |
| topic | sims surface intermetallic alloy lanthanum alloy lani5 hydrogen metal hydride oxygen oxides |
| url | https://periodicals.karazin.ua/eejp/article/view/22116 |
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