Pavlyuk N. Interaction of magnesium with lithium, d-metals (Mn, Fe, Co, Ni) and p-elements (Al, Ga, Ge, Sn)

Українська версія

Thesis for the degree of Doctor of Philosophy (PhD)

State registration number

0823U100630

Thesis Registration Form

0823U100630.pdf

Applicant for

Specialization

  • 102 - Хімія

07-09-2023

Specialized Academic Board

ДФ 35.051.113_ID 1994

Ivan Franko National University of Lviv

Essay

The thesis presents experimental results from the study of the interaction of components in the ternary systems Mg-{ Mn, Fe, Co, Ni}-{Ga, Al, Ge, Sn} and Mg-Li-Al, crystal and electronic structures, electrochemical, sorption, magnetic and electrical properties of magnesium-based ternary phases. For the Mg-Ni-Ga system, an isothermal section at 200 °C was constructed for the first time and the existence of seven ternary compounds τ1– MgNi1+xGa1-x (structure type MgCu2), τ2– MgNiGa (structure type MgZn2), τ3– Mg2NiGa3 (structure type Mg2MnGa3 ), τ4– Mg9-xNi6Ga14-y (new structure type, Fd-3m, a = 19.8621(6) Å), τ5– MgNi2Ga2 (structure unknown), τ6– MgNi2Ga5 (structure type MgCo2Ga5); τ7– MgNi6Ga6 (structure type ScFe6Ga6); τ8– Mg3Ni2Ga (structure type Mn3Ni2Si). For the Mg-Co-Ga system, for the first time, an isothermal section of diagrams at 200 °C was constructed. The existence of four new intermetallics, which are new structure types, was established: τ1– MgCo2Ga5 (space group Pnnm, a=6.2486, b=6.6652, c=6.0523 Å; τ3– MgCoGa2 (P21/c, a=5.1505(2) Å, b=7.2571(2) Å, c=8.0264(3) Å, β=125.571(3); τ4– Mg0,74CoGa0,52 (Cmcm, a=4.9868(9), b=25.959(4), c=8.0508(11) Å); τ5– Mg0,49CoGa0,15 (R-3m, a=4.9296(2), c=12.0744(7) Å). An isothermal section of the Mg-Mn-Ga system at 200 °C was constructed and the existence of six ternary compounds was established: τ1– MgMn4Ga18 (new structure type), τ2– MgMn2Ga5 (structure type MgCo2Ga5), τ3– Mg2MnGa3 (new structure type), τ4– MgMn0, 7Ga1,3 (MgZn2 type), τ5– Mg2Mn6Ga5 (Cu5Zn8 structure type), τ6– Mg2Mn2Ga (β-Mn structure type). The phases Mg2MnGa3 (Cmcm, a=5.4324(1), b=8.6959(3), c=8.5858(2) Å) and MgMn4Ga18 (P4/mmm, a = 8.3116(9), c = 9.944(2) Å) are new structure types. In the studied phase diagrams of Mg-{Mn, Co, Ni}-Ga systems, regions of homogeneity of ternary phases were established and the solubility of the third component in binary phases was determined. The most extensive are solid solutions based on Laves phases. In addition to the above-described phase equilibria in the Mg-{Mn, Co, Ni}-Ga systems, the rest of the Mg-{Mn, Fe, Co, Ni}–{Al, Ge, Sn} and Mg-{Fe}–Ga systems were studied for formation of ternary compounds. In the studied and related systems, the existence of 14 known and 38 new intermetallic compounds was confirmed by single crystal and powder methods. Crystal structures belonging to 29 structural types, 8 of which are new, have been determined for all synthesized new compounds. Most of the studied compounds belong to two families of intermetallics. The first – derivatives of Laves phases, and the second – cluster intermetallics. Magnetic properties were studied for the synthesized phases. The most interesting compounds were Mg2Mn2Al and MgMn4Ga18. The Mg2Mn2Al phase, which crystallizes in the β-Mn structure type, can be classified as soft ferromagnets. Based on the results of studying the dependence of magnetic susceptibility on temperature and magnetization curves, it was found that for the compound MgMn4Ga18 there is mainly a positive susceptibility that does not depend on temperature (Pauli paramagnetism) in the range from 6 K to 300 K. A sharp drop in susceptibility below 6 K with diamagnetic behavior indicates the existence of superconductivity below 6 K. With the help of electrochemical studies, intermetallics with a Laves phase type of structure were tested as anode materials for batteries. The observed results showed that they are characterized by a high discharge capacity (up to 80 mAh/g), the electrodes are easily activated, which allows them to be used in real metal hydride batteries. Gas hydrogenation also confirms their high sorption capacity up to 2.5 wt % H2. It was established that for Laves phases, the replacement of d-metal by p-element improves the absorption capacity.

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Research papers

1. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., & Ehrenberg, H. (2019). Li20Mg6Cu13Al42: a new ordered quaternary superstructure to the icosahedral T-Mg32(Zn,Al)49 phase with fullerene-like Al60 cluster. Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, 75(2), 168-174. (Scopus, Q1).

2. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., Rozdzynska-Kielbik, B., Nitek, W., Lasocha, W., Chumak, I., Ehrenberg, H. (2020). A new monoclinic structure type for ternary gallide MgCoGa2. Acta Crystallographica Section C: Structural Chemistry, 76(6), 541-546. (Scopus, Q4).

3. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., Rozdzynska-Kielbik, B., Cichowicz, G., Cyranski, M. K., Chumak, I., Ehrenberg, H. (2020). New cubic cluster phases in the Mg–Ni–Ga system. Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, 76(4), 534-542. (Scopus, Q1).

4. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., Rożdżyńska-Kiełbik, B., Gil, A., Chumak, I., & Ehrenberg, H. (2020). New ternary MgCo2Ga5 and MgNi2Ga5 gallides. Zeitschrift für Kristallographie-Crystalline Materials, 235(11), 513-521. (Scopus, Q3).

5. Pavlyuk, N., Chumak, I., Pavlyuk, V., Ehrenberg, H., Indris, S., Hlukhyy, V., & Pöttgen, R. (2022). Mg2MnGa3 – An orthorhombically distorted superstructure variant of the hexagonal Laves phase MgZn2. Zeitschrift für Naturforschung B, 77(10), 727-733. (Scopus, Q3).

6. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., Chumak, I., Indris, S., & Ehrenberg, H. (2022). Mg-Ni-Ga System: Phase Diagram, Structural and Hydrogenation Properties of MgNi1.25Ga0.75, MgNiGa, and Mg2NiGa3. Journal of Phase Equilibria and Diffusion, 43(4), 458-470. (Scopus, Q2).

7. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., Chumak, I., Indris, S., Schwarz, B., & Ehrenberg, H. (2022). MgMn4Ga18: a novel three-shell gallium cluster structure. Acta Crystallographica Section C: Structural Chemistry, 78(8), 455-461. (Scopus, Q4).

8. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., Ciesielski, W., Rozdzynska-Kielbik, B., Indris, S., & Ehrenberg, H. (2023). A new ternary derivative of the Laves phases in the Mg–Co–Ga system. Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, 79(4). (Scopus, Q2).

9. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., Ehrenberg, H. (2019). New cubic Li20Mg6Cu13Al24Si18 ordered high entropy phase. Тези ХVІI наукової конференції «Львівські хімічні читання – 2019». Львів, 2-5 червня 2019, Н-1.

10. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., Cichowicz, G., Cyrański, M.K., Ehrenberg, H. (2019). New cubic phases in the Mg–Ni–Ga system. Coll. abs. XIV International Conference of Crystal Chemistry of Intermetallic Compounds., Lviv, Ukraine, September 22–26, 2019, 111.

11. Pavlyuk, N., Dmytriv, G., Ciesielski, W., Pavlyuk, V., Ehrenberg, H. (2020). Crystal structure of Mg0.23NiSn1.77. Abstracts of the XXII International Seminar of Physics and Chemistry of Solids and advanced Materials, Lviv, 17-19 June 2020, 21.

12. Pavlyuk, N., Dmytriv, G., Ciesielski, W., Pavlyuk, V. (2021) Crystal structure of the novel MgT6Ga6 (T=Ni, Pd) ternary compounds. International Conference on Solid Compounds of Transition Elements SCTE 2021, Wrocław, Poland, 12-15 April 2021, 202.

13. Pavlyuk, N., Dmytriv, G., Ciesielski, W., Pavlyuk, V. (2021). New cubic disordered phase of Mg6Ni16+xGe7+y (x=0.05, y=0.36). ХVІII наукова конференція «Львівські хімічні читання – 2021», 31 травня – 2 червня 2021 р., Н17.

14. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., Indris, S., Schwarz, B. (2022). MgMn4Ga18: new structural type with three core-shell cluster packing. 33rd European Crystallographic Meeting: Book of abstracts, Versailles, France, August 23-27, 2022, 498-499.

15. Pavlyuk, N., Dmytriv, G., Pavlyuk, V., Ehrenberg, H. (2022). Crystal structures of intermetallic compounds with core-shell clusters. New point of view. Current problems of chemistry, materials science and ecology: Proceedings, Lutsk, Ukraine, 1-3 June 2022, 12.

16. Pavlyuk, N., Dmytriv, G., Pavlyuk, V. (2023) A new ternary derivative of the Laves phases in the Mg-Co-Ga system. ХІX Наукова конференція "Львівські хімічні читання - 2023". 29–31 травня 2023.

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