ИСТИНА

Synthesis of hydrides of LaNi5 and RT3 (CeCo3, NdNi3, GdFe3, DyCo3 and ErNi3) intermetallic compounds has been performed at low temperature (about 273 K) and pressure of hydrogen up to 100 atm. Lattice parameters of hydrides were analyzed using X-ray diffraction method. Amount of hydrogen was measured by temperature extraction method. Formed hydride phases after heating to room temperature have increased or stoichiometry hydrogen composition in comparison with their low-pressure prototypes, described in literature. Samples of CeCo3 and GdFe3 hydrides have two phases, first are pure IMC and second are hydride phase. A sample of ErNi3 hydride after second cycle is triple phase, and consists from pure IMC and two hydride phases. All hydrides have increased stability and slowly decompose at air and room temperature: hydride of LaNi5 about one day and RT3 hydrides during several months. Similar stability was revealed for LaNi5, CeCo3, GdFe3 and ErNi3 hydrides synthesized under high-pressure (up to 2000 atm) with irreversibility of hydrogen desorption after hydrogenation [1, 2, 3]. In our case, formation of stable hydrides with composition, close to stoichiometry occurred at relatively low pressure (about 100 atm) and low temperature. In literature analogous behavior of hydrogen first was observed in metal sublattice of hydride phases of d-metals (V, Nb, Ta). It was revealed, that this takes place due to hydrogen redistribution in metal matrix of hydride phases [4]. References [1] J. F. Lakner, F.S. Uribe, S.A. Steward, J. Les-Comm. Met. 72(1980) 87. [2] V.N. Verbetsky, S.N. Klyamkin, A. Yu. Kovriga, A.P. Bespalov, Int. J. Hydrogen Energy, 11/12, 21(1996) 997. [3] S.A. Lushnikov, S.N. Klyamkin, V.N. Verbetsky, J.Alloys Compd. 330-332 (2012) 574. [4] H. Asano, M. Hirabayashi, Phys. State. Sol. (A), 16 (1973) 69.