Peculiarities of thermoelectric half-Heusler phase formation in Gd-Ni-Sb and Lu-Ni-Sb ternary systems

Journal Article · Fri Jul 15 04:00:00 EDT 2016 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2016.04.029· OSTI ID:22584155

Romaka, L.; Horyn, A. ^[1]; Rogl, P. ^[2]; Stadnyk, Yu; Melnychenko, N. ^[1]; Orlovskyy, M.; Krayovskyy, V. ^[3]

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1. Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya str. 6, 79005 Lviv (Ukraine)
2. Institute of Materials Chemistry and Research, University of Vienna, Währingerstrasse 42, A-1090 Wien (Austria)
3. Department of Applied Material Science and Materials Engineering, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine)

The phase equilibria in the Gd–Ni–Sb and Lu-Ni-Sb ternary systems were studied at 873 K by X-ray and metallographic analyses in the whole concentration range. The interaction of the elements in the Gd–Ni–Sb system results the formation of five ternary compounds at investigated temperature: Gd{sub 5}Ni{sub 2}Sb (Mo{sub 5}SiB{sub 2}-type), Gd{sub 5}NiSb{sub 2} (Yb{sub 5}Sb{sub 3}-type), GdNiSb (MgAgAs-type), Gd{sub 3}Ni{sub 6}Sb{sub 5} (Y{sub 3}Ni{sub 6}Sb{sub 5}-type), and GdNi{sub 0.72}Sb{sub 2} (HfCuSi{sub 2}-type). At investigated temperature the Lu-Ni-Sb system is characterized by formation of the LuNiSb (MgAgAs-type), Lu{sub 5}Ni{sub 2}Sb (Mo{sub 5}SiB{sub 2}-type), and Lu{sub 5}Ni{sub 0.56}Sb{sub 2.44} (Yb{sub 5}Sb{sub 3}-type) compounds. The disordering in the crystal structure of half-Heusler GdNiSb and LuNiSb was revealed by EPMA and studied by means of Rietveld refinement and DFT modeling. The performed electronic structure calculations are in good agreement with electrical transport property studies. - Graphical abstract: Crystal structure model and electron localization function of Lu{sub 5}Ni{sub 2}Sb. Display Omitted - Highlights: • Gd-Ni-Sb and Lu-Ni-Sb phase diagrams were constructed at 873 K. • GdNiSb and LuNiSb are characterized by disordered crystal structure. • Crystal structure optimization with DFT calculations confirmed crystal structure disorder in GdNiSb and LuNiSb.

• OSTI ID: 22584155
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 239; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ANTIMONIDES
CONCENTRATION RATIO
CRYSTAL STRUCTURE
CRYSTALS
ELECTRON MICROPROBE ANALYSIS
ELECTRONIC STRUCTURE
ELECTRONS
GADOLINIUM
INTERACTIONS
METALLOGRAPHY
NICKEL
PHASE DIAGRAMS
SIMULATION
TIN
X RADIATION