Development of technology for high-strength thermoelectrics with a diameter of up to 35 mm based on Bi-=SUB=-2-=/SUB=-Te-=SUB=-3-=/SUB=- polycrystals by hot extrusion

Abstract

Hot extrusion of thermoelectric materials of large diameters is associated with the problem of preserving the deformation texture in them both in length and in cross-section. The paper shows for the first time the technology of obtaining polycrystals based on Bi2Te3 n- and p-type conductivity with a diameter of up to 35 mm, by hot extrusion. Detailed studies of the structural properties have been carried out. The mechanical properties (strength) of the crystals were measured. The thermoelectric properties of polycrystals of various diameters (the coefficient of thermal EMF α, electrical conductivity sigma and figure of merit Z by the Harman method) were measured. It is shown at the optimal technology polycrystals based on Bi2Te3 n- and p-type conductivity with a diameter of 35 mm were produced, which are comparable in thermoelectric and mechanical properties with polycrystals of traditional diameter (25 and 30 mm), which are currently commercially produced. Keywords: thermoelectricity, Bi2Te3, extrusion, thermoelectric properties, mechanical properties.