METAL PROCESSING | |
ArticleName | To the problem of positive sign of thermal E. M. F of metallic systems |
ArticleAuthor | Selyanin I. F., Deev V. B., Kutsenko A. I., Prikhodko O. G. |
ArticleAuthorData | Siberian State Industrial University, Novokuznetsk, Russia: I. F. Selyanin, Professor (Chair of Materials Science, Foundry and Welding Fabrication) V. B. Deev, Chief Researcher of Engineering Center “Foundry Technologies and Materials”, Professor of a Chair of Foundry Processes Technology |
Abstract | This work shows that absolute thermal e. m. f of metallic systems can have negative and positive signs, as it was experimentally defined. Logically, negative sign of Seebeck effect arises from the solution of Boltzmann kinetic equation, because basically, electrons transfer heat and charge in metals under the temperature gradient influence. However, the issue of a positive sign of thermal e. m. f is still urgent. Positive sign of thermal e. m. f in most researches of this area was connected with peculiarities of behavior of Fermi electrons on the boundaries of the given energy band and with deviation of Fermi surface from spherical shape. There is shown that existing formulas on thermal e. m. f of various researchers were established for metals in solid state, when their structure is lattice. It is very urgent to consider the Brillouin zone, electrons scattering anisotropy on these Fermi surface areas, influence of normal (N) and umklapp (U) processes on final thermal e. m. f sign. The long-range order, leading to appearance of Brillouin zones and other effects, connected with peculiarities of Fermi surface, is absent in liquid metals. That’s why, the difference between normal, umklapp and other processes, typical for solid crystalline bodies, has no sense. The theory of positive sign of thermal e. m. f of most metallic systems in solid and liquid states has not been developed yet. Solution of this problem allows metallurgists and metallographers to connect the results of thermal treatment, plastic deformation and other external impacts on materials with parameters of their energetic spectrum of electrons, basing on the data of thermal electric properties of metals and alloys. |
keywords | Absolute thermal e. m. f, Fermi surface, metallic systems, electrons, Brillouin zone, thermal electric properties, energetic spectrum of electrons |
References | 1. Livshits B. G., Kraposhin V. S., Linetskiy V. L. Fizicheskie svoystva metallov i splavov (Physical properties of metals and alloys). Moscow : Metallurgiya, 1980. 320 p. |
Language of full-text | russian |
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