National Research University «MISiS»

K. V. Gochua

The effect of the initial billet (molded material obtained by zone melting, without grinding and a powder of the same material of 150—200 μm particle size) on the texture of the extruded materials obtained at the given technological conditions is examined. It is shown that no significant difference in the texture of the material is found. The deformation texture and the degree of structural imperfection are studied in order to apply the property anisotropy of TEM and the donor effect to enhance thermoelectric efficiency of the extruded samples. It is established that at the particle size of the initial powder of 150−200 μm electrophysical parameters are maximally implemented and the impact of the «donor effect» on thermoelectric properties was optimal, i.e. the optimal value of the power factor α²σ is obtained. The physical model explaining the mechanism of occurrence of the donor effect in the extrusion process is proposed.

1. Bublik, V. T. Formirovanie struktury v protsesse goryachey ekstruzii sterzhney termoelektricheskikh tverdykh rastvorov na osnove khal'kogenidov vismuta / V. T. Bublik, V. V. Karataev, V. B. Osvenskiy, N. Yu. Tabachkova // Izv. vuzov. Materialy elektron. tekhniki. − 2009. − № 2. − S. 49—52.
2. Gorelik, S. S. Rekristallizatsiya i elektricheskie svoystva nizkotemperaturnykh termoelektricheskikh materialov, ekstrudirovannykh iz keramicheskikh zagotovok / S. S. Gorelik, A. N. Dubrovina, V. L. Ablamskiy, R. Kh. Leksina // Izv. AN SSSR. Neorgan. materialy. − 1977. − T. 13. − № 11. − S. 1997—2000.
3. Gorelik, S. S. Pervichnaya rekristallizatsiya i rekristallizatsiya in situ ekstrudirovannykh materialov s reshetkoy tetradimita / S. S. Gorelik, A. N. Dubrovina, R. Kh. Leksina, G. A. Drozdova // Tam zhe. − 1977. − T. 13. − № 11. − S. 1991—1996.
4. Gorelik, S. S. O vliyanii razmera chastits na svoystva tverdykh rastvorov na osnove tellurida vismuta pri ekstruzii polikristallicheskikh zagotovok / S. S. Gorelik, V. L. Ablamskiy // V sb.: Struktura i svoystva termoelektricheskikh materialov. − M. : MISiS, 1974. − S. 95—99.
5. Sootsman, J. R. Strong reduction of thermal conductivity in nanostructured PbTe prepared by matrix encapsulation / J. R. Sootsman, R. J. Pcionek, H. Kong, C. Uher, M. G. Kanatzidis // Chemistry of Mater. − 2006. − V. 18, N 21. − P. 4993–4995.
6. Vasilevskiy, D. Hot extruded (Bi,Sb)₂(Te,Se)₃ alloys for advanced thermoelectric modules / D. Vasilevskiy, N. Kukhar, S. Turenne, R. A. Masut // Proc. 5^th Europ. Conf. on Thermoelectrics. − Odessa (Ukraine), 2007.
7. Gochua, K. V. Izuchenie zakonomernostey formirovaniya i vliyaniya struktury na svoystva termoelektricheskikh materialov na osnove khal'kogenidov Bi i Sb, poluchennykh metodom vertikal'noy napravlennoy kristallizatsii / K. V. Gochua // Izv. vuzov. Materialy elektronnoy tekhniki. − 2011. − № 4. − S. 56—61.
8. Bublik, V. T. Metody issledovaniya struktury poluprovodnikov i metallov / V. T. Bublik, A. N. Dubrovina. − M. : Metallurgiya, 1978. − 272 s.
9. Dudkin, L. D. K teorii rastvorimosti elektroaktivnykh primesey v poluprovodnikakh / L. D. Dudkin, R. O. Erofeev, E. L. Nagaev // Izv. AN SSSR. Neorgan. materialy. − 1967. − T. 3, № 8. − S. 1375−1378.
10. Gorelik, S. S. Rekristallizatsiya metallov i splavov / S. S. Gorelik. − M. : Metallurgiya, 1967. − 404 s.