THERMAL AND ELECTRIC FIELDS AT SPARK PLASMA SINTERING OF THERMOELECTRIC MATERIALS

L. P. Bulat, D. A. Pshenai-Severin, I. A. Nefedova, A. V. Novotelnova, Y. G. Gurevich


Read the full article 

Abstract

Problem statement. Improvement of thermoelectric figure of merit is connected with the usage of nanostructured thermoelectric materials fabricated from powders by the spark plasma sintering (SPS) method.  Preservation of powder nanostructure during sintering is possible at optimum temperature modes of thermoelectrics fabrication. The choice of these modes becomes complicated because of anisotropic properties of semiconductor thermoelectric materials. The decision of the given problem by sintering process simulation demands the competent approach to the problem formulation, a correct specification of thermoelectric properties, the properties of materials forming working installation, and also corrects boundary conditions. The paper deals with the efficient model for sintering of thermoelectrics. Methods.  Sintering process of the bismuth telluride thermoelectric material by means of SPS-511S installation is considered. Temperature dependences of electric and thermal conductivities of bismuth telluride, and also temperature dependences of installation elements materials are taken into account. It is shown that temperature distribution in the sample can be defined within the limits of a stationary problem. The simulation is carried out in the software product Comsol Multiphysics. Boundary conditions include convective heat exchange and also radiation under Stefan-Boltzmann law. Results. Computer simulation of electric and thermal processes at spark plasma sintering is carried out. Temperature and electric potential distributions in a sample are obtained at the sintering conditions. Determinative role of graphite compression mould in formation of the temperature field in samples is shown. The influence of geometrical sizes of a graphite compression mould on sintering conditions of nanostructured thermoelectrics is analyzed. Practical importance. The optimum sizes of a cylindrical compression mould for fabrication of volume homogeneous samples based on bismuth telluride are determined. Ways of updating for the sintering process are shown giving the possibility to fabricating thermoelectric samples with predicted properties.


Keywords:  spark plasma sintering, thermoelectric materials, nanostructures, computer simulation, thermoelectric figure of merit, thermal conductivity, thermal and electric fields

Acknowledgements. The work is supported by the Ministry of Education and Science of the Russian Federation (grant № 14.579.0039 and task № 3.912.2014/К).

References
 1. Bulat L.P., Drabkin I.A., Karatayev V.V., Osvenskii V.B, Parkhomenko Yu.N., Lavrentev M.G., Sorokin A.I., Pshenai-Severin D.A., Blank V.D., Pivovarov G.I., Bublik V.T., Tabachkova N.Yu. Structure and transport properties of bulk nanothermoelectrics based on BixSb2−xTe3 fabricated by SPS method. Journal of Electronic Materials, 2013, vol. 42, no. 7, pp. 2110–2113. doi: 10.1007/s11664-013-2536-9
2. Drabkin I.A., Osvenskii V.B., Sorokin A.I., Bulat L.P., Pivovarov G.I. Anizotropiya termoelektricheskikh svoistv ob"emnogo nanostrukturirovannogo materiala na osnove (Bi,Sb)2Te3, poluchennyi metodom iskrovogo plazmennogo spekaniya (SPS) [Anisotropy of the thermoelectric properties of the bulk nanostructured material based on (Bi,Sb)2Te3, obtained by spark plasma sintering (SPS)]. Proc. Intergovernmental Seminar of Thermoelectrics and Their Applications. St. Petersburg, 2013, pp. 29–34.
3. Bublik V.T., Drabkin I.A., Karataev V.V., Lavrent'ev M.G., Osvenskii V.B., Bulat L.P., Pivovarov G.I., Sorokin A.I., Tabachkova N.Yu. Ob"emnyi nanostrukturirovannyi termoelektricheskii material na osnove (Bi,Sb)2Te3, poluchennyi metodom iskrovogo plazmennogo spekaniya (SPS) [Volumetric nanostructured thermoelectric material based on (Bi,Sb)2Te3, obtained by spark plasma sintering (SPS)]. Proc. Intergovernmental Seminar of Thermoelectrics and Their Applications. St. Petersburg, 2013, pp. 23–28.
4. Drabkin I.A., Osvenski V.B., Parkhomenko Yu.N., Sorokin A.I., Pivovarov G.I., Bulat L.P. Anisotropy of thermoelectric properties of р-type nanostructured material based on (Bi, Sb)2Te3. Journal of Thermoelectricity, 2013, no. 3, pp. 35–46.
5. Bulat L.P., Osvenskii V.B., Parkhomenko Y.N., Pshenay-Severin D.A. Investigation of the possibilities for increasing the thermoelectric figure of merit of nanostructured materials based on Bi2Te3-Sb2Te3 solid solution. Physics of the Solid State, 2012, vol. 54, no. 11, pp. 2168–2172. doi: 10.1134/S1063783412110054
6. Bulat L.P., Osvenskii V.B., Pshenay-Severin D.A. Influence of grain size distribution on the lattice thermal conductivity of Bi2Te3-Sb2Te3-based nanostructured materials. Physics of the Solid State, 2013, vol. 55, no. 12, pp. 2442–2449. doi: 10.1134/S1063783413120081
7. Bulat L.P., Drabkin I.A., Karatayev V.V., Osvenskii V.B., Parkhomenko Yu.N., Pshenay-Severin D.A., Sorokin A.I. The influence of anisotropy and nanoparticle size distribution on lattice thermal conductivity and the thermoelectric figure of merit in nanostructured (Bi,Sb)2Te3. Journal of Electronic Materials, 2014, vol. 43, no. 6, pp. 2121–2126. doi: 10.1007/s11664-014-2988-6.
8. Anselmi-Tamburini U., Gennari S., Garay J.E., Munir Z.A. Fundamental investigations on the spark plasma sintering/synthesis process: II. Modeling of current and temperature distributions. Materials Science and Engineering, 2005, vol. 394, no. 1–2, pp. 139–148. doi: 10.1016/j.msea.2004.11.019
9. Cengel Y.A., Ghajar A.J. Heat and Mass Transfer. 4th ed. McGraw-Hill, 2011, 960 p.
10. Total Emissivity of Various Surfaces. 2003. Available at: http://www.contika.dk/Download/litteratur/emission.pdf (accessed 11.05.2014).
 11. Overall Heat Transfer Coefficients for Some Common Fluids and Heat Exchanger Surfaces. Available at: http://www.engineeringtoolbox.com/overall-heat-transfer-coefficients-d_284.html (accessed 11.05.2014).
12. Hust J.G. Standard Reference Materials: a Fine-Grained, Isotropic Graphite for Use as NBS Thermophysical Property RMs from 5 to 2500 K. NBS Special Publication 260-89, 1984. Available at: http://www.nist.gov/srm/upload/SP260-89.PDF (accessed 11.05.2014).
13. Grafitovaya Fol'ga Grafleks [Graphite Foil Grafleks]. 2010. Available at: http://traverss.ru/grafitovaya_folga_graf (accessed 11.05.2014).
14. Hust J.G., Giarratano P.J. Standard Reference Materials: Thermal Conductivity and Electrical Resistivity Standard Reference Materials: Austenitic Stainless Steel, SRMs 735 and 798, from 4 to 1200 K. NBS Special Publication 260-46, 1975. Available at: http://www.nist.gov/srm/upload/SP260-46.PDF (accessed 11.05.2014).
15. Magomedov Ya.B., Gadzhiev G.G., Omarov Z.M. Temperaturnaya zavisimost' teploprovodnosti i elektroprovodnosti Bi2Te3 i ego rasplava [The temperature dependence of the thermal conductivity and the electrical conductivity of Bi2Te3 and its melt]. Fazovye Perekhody, Uporyadochennye Sostoyaniya i Novye Materialy, 2013, no. 9, pp. 1–5.
 16. Stecker K., Süssmann H., Eichler W., Heiliger W., Stordeur M. Martin-Luther Univ. Halle-Wittenberg. Math-Naturwiss, 1978, vol. 27, no. 5, p. 5.
Copyright 2001-2017 ©
Scientific and Technical Journal
of Information Technologies, Mechanics and Optics.
All rights reserved.

Яндекс.Метрика