On the constitution and thermodynamic modelling of the system Zr-Ni-Sn
- Autor(en)
- Philipp Sauerschnig, Andrij Grytsiv, Jan Vrestal, Vitaliy A. Romaka, Bedřich Smetana, Gerald Giester, E. Bauer, Peter Franz Rogl
- Abstrakt
In continuation of our optimization of {Ti, Zr} NiSn- based thermoelecs., we herein detd. the constitution of the system Zr- Ni- Sn (liquidus surface and isothermal section at 950 °C) employing X- ray powder diffraction (XPD) and electron probe micro anal. (EPMA) of about 80 ternary alloys in as cast and annealed state. The system is characterized by the existence of four ternary compds. labeled t1 to t4. At 950 °C no significant homogeneity regions are found for the compds. t1- ZrNiSn (Half- Heusler phase, MgAgAs- type) , t2- ZrNi2Sn (Heusler phase, MnCu2Al- type) and t4- Zr6NiSn2 (K2UF6- type, ordered Fe2P- type) , but t3- Zr2+xNi2+ySn1- x- y exhibits a significant soln. range for 0.0 = x = 0.25 and 0.0 = y = 0.06. Extended solid solns. starting from binary phases at 950 °C have been evaluated for Zr5(Nix ySn1- x- y) 4 (filled Mn5Si3 - Ti5Ga4- type; 0 = x = 0.216, 0.002 = y = 1) and Zr1- x(Ni1- ySny) 5+x (AuBe5- type) reaching a max. soly. at x = 0.022, y = 0.146 (the symbol denotes a vacancy) . From DTA (DTA) measurements a complete liquidus surface has been elucidated revealing congruent melting for t1- ZrNiSn (at 1465 ± 10 °C) and t2- ZrNi2Sn at 1469 ± 10 °C, but incongruent melting for t3- Zr2Ni2Sn (pseudobinary peritectic formation: l + Zr5(Nix ySn1- x- y) 4 t3 at 1406 ± 10 °C) , and for t4- Zr6NiSn2 (ternary P- type reaction: L + Zr5(Nix ySn1- x- y) 4 + (Zr) t4- Zr6NiSn2 at 1124 ± 8 °C) . A Schultz- Scheil diagram for the solidification behavior was constructed for the entire diagram. X- ray single crystal data have defined precise atom site occupancies in t4- Zr6NiSn2 (RF2 = 0.0113) as well as close to the end point of the solid soln. Zr5Ni1- xSn3 (stuffed Mn5Si3- type; x = 0.21, RF2 = 0.0238) and isostructural Hf5Ni1- xSn3 (x = 0.26, RF2 = 0.0242) . As thermodn. data in the ternary system were only available in the literature for ZrNiSn, heat of formation data were supplied by our DFT calcns. for ZrNi2Sn, Zr2Ni2Sn and Zr6NiSn2 as well as for the solid solns. Zr5(Nix ySn1- x- y) 4 and Zr1- x(Ni1- ySny) 5+x for y = 0 and x = 0.25 or y = 0.20. For these cases DFT calcns. also provide details on electronic properties and bonding. Thermodn. CALPHAD calcn. was performed with the Pandat software and resulted in reasonably good agreement for all the 29 invariant reaction isotherms involving the liq.
- Organisation(en)
- Institut für Materialchemie, Institut für Mineralogie und Kristallographie
- Externe Organisation(en)
- Technical University of Ostrava, Christian Doppler Forschungsgesellschaft (CDG), Technische Universität Wien, Masaryk University, Lviv Polytechnic National University
- Journal
- Journal of Alloys and Compounds
- Band
- 742
- Seiten
- 1058-1082
- Anzahl der Seiten
- 25
- ISSN
- 0925-8388
- DOI
- https://doi.org/10.1016/j.jallcom.2017.12.012
- Publikationsdatum
- 04-2018
- Peer-reviewed
- Ja
- ÖFOS 2012
- 104017 Physikalische Chemie, 104011 Materialchemie, 105113 Kristallographie
- Schlagwörter
- ASJC Scopus Sachgebiete
- Mechanics of Materials, Mechanical Engineering, Metals and Alloys, Materials Chemistry
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/1cf36a37-5013-4ad5-922f-7057adcea718