Correlation between cross-section distribution of thermoelectric parameters of Sb2Te3-based material and its stress–strain state during hot extrusion

Abstract

In this work, p-type thermoelectric material was produced by hot extrusion of pre-synthesized in injection molding machine BixSb2-xTe3 ternary solid solution with x ≈ 0.4. Temperature dependences of its thermoelectric parameters were investigated in the range of 230–370 K. Extruded material exhibits a single phase of Bi-Sb-Te, about >97% relative density, electrical conductivity at about 1000 (Ω·cm)−1 and the Seebeck coefficient at about 210 μV/K at room temperature. Besides it is characterized by a significant heterogeneity of thermoelectric properties in its cross-section with spreadings of the Seebeck coefficient S ± 2.5% and electrical conductivity σ ± 10%. Such heterogeneity correlates with stress–strain state nonuniformity that has been shown using mathematical modeling of the hot extrusion process.