Аналіз зміни термоелектрорушійної сили термоелектродів внаслідок їх відносної деформації

Abstract

Проаналізовано вплив механічної деформації матеріалів термоелектродів вимірювальних термоперетворювачів на зміну їх термоелектрорушійної сили.

In order to reduce the uncertainty of the result obtained during the measurement of high temperatures by thermoelectric transducers in the adverse conditions of operation, particulary in case of rapid thermal changes, the influence of mechanical deformation of thermoelectrodes on the change of their thermoelectric power is analyzed. Taking into account that the energy spectrum of electrons in metals is determined by their number and potential of a crystalline lattice, we assume that in the case of elastic deformation with displacement of ions, the lattice potential also varies. Proceeding from the principle of preserving the electroneutrality of the metal, it becomes evident that simultaneously with the change in the lattice potential during deformation there should be a change in the energy spectrum of the electrons, which is manifested through the change in the electrokinetic properties of the metal. It is known that thermoelectric power is determined by the electronic structure near the Fermi surface, and its change is related with the change in topology of this surface. The relationship between the area of the Fermi surface and the thermoelectric power source, caused by the elastically deformed state of the thermoelectric material, is considered. If the point of contact is deformed – the undeformed material is maintained at a certain constant gradient of temperature, then in the circle there will be thermoelectric power, caused by the temperature dependence of the electrochemical potentials of deformed and non-deformed materials. Dependences are obtained for the determination of thermoelectric power change. materials of thermoelectrodes in the function of relative mechanical deformation, which, in the case of taking into account these dependencies at the design stage of thermoelectric thermal converters, makes it possible to increase their metrological characteristics when measuring high temperatures in aggressive environments, particulary, in the coke industry and metallurgy.

Проанализировано влияние механической деформации материалов термоэлектродов измерительных термопреобразователей на изменение их термоэлектродвижущей силы.