Ізотермічний переріз діаграми стану потрійної системи Tb-Li-Si за температури 400ºС

Abstract

The isothermal cross-section of the phase diagram of the system Tb-Li-Si based on X-ray phase and local X-ray spectral analyses was constructed at the temperature 400 ºС in the range 30-100 аt. % Si. The alloys were prepared by arc melting of stoichiometric amounts of the constituent elements, annealed at 400 ºС for 480 hours and quenched in cold water. The calculations and indexing powder diffraction were conducted using software LATCON and POWDER CELL-2.3. Calculations to refine the structure of the samples were carried out by means of programs CSD and 98 FullProf. Five new ternary compounds have been synthesized for the first time: TbLiSi2 (SТ NdRuSi2, Pearson symbol mP8, space group P21/m, a = 0,4015(1), b = 0,3874(1), c = 0,8122(2) nm, β = 102,32°), TbLiSi (SТ ZrNiAl, Pearson symbol hP9, space group P-62m, a = 0,7016(1), c = 0,4202(1) nm), TbLi0,35Si1,65 (SТ α-ThSi2, Pearson symbol tI12, space group I41/amd, a = 0,4046(3), c = 1,3917(7) nm), TbLi5Si4 (unknown structure) and TbLi3Si(unknown structure). All these compounds have been refined using powder X-ray diffraction data (diffractometers DRON-2,0 (FеКα- radiation), STOE STADI P (CuKα-radiation) and URD-6 (CuKα-radiation)). The existence of the binary phases TbSi2-x, TbSi2, TbSi, Tb5Si4, Tb5Si3, Li22Si5, Li13Si4, Li14Si6, Li12Si7, Li2Si was confirmed. The solubility of the third component in the binary compounds at 400 ºС was not observed. The characteristics of phase interactions in the Tb-Li-Si as well as related systems with rare earth metals, Lithium and Silicon have been analysed.