Microstructure and thermoelectric properties of extruded n-type 95%Bi 2Te 2–5%Bi 2Se 3 alloy along bar length

Abstract

n-Type SbI 3-doped 95%Bi 2Te 3–5%Bi 2Se 3 compounds were prepared by a gas atomization and extrusion at 450 °C in the ratio 25:1. The dynamic recrystallization and thermoelectric properties of the compounds along extruded bar were investigated by a combination of microscopy, XRD and thermoelectric property testing. The microstructure of extruded bar shows homogeneous and fine distribution through full length due to dynamic recrystallizaiton during hot extrusion. The Seebeck coefficient at extruded bar length of 70 mm is 160 μV K −1 and with increasing extruded bar length to 260 and 780 mm, the Seebeck coefficient is 150 and 154 μV K −1, respectively. The electrical resistivity of 70 mm bar length is about 0.677×10 −5 Ωm and with increasing the length to 260 and 780 mm, the value is 0.510 and 0.587×10 −5 Ωm.