Thermoelectric properties of n-type 95%Bi2Te3–5%Bi2Se3 materials fabricated by magnetic pulsed compaction (MPC)

The n-type 95%Bi2Te3–5%Bi2Se3 doped with 0.04% SbI3 thermoelectric powders were produced by gas atomization process, and subsequently consolidated by magnetic pulsed compaction (MPC) technique at different temperatures into the bulks, and finally, their room temperature thermoelectric and mechanical properties in both perpendicular and parallel sections to the pressing direction were evaluated as a function of various consolidation temperatures. Microstructural observation of both the powder and bulk was carried out by scanning electron microscopy (SEM) and optical microscopy (OM), and the crystal structures were analyzed by XRD. The maximum Vickers hardness of 65–66 Hv and the maximum Seebeck coefficient of around 159 μV/K was obtained in both perpendicular and parallel sections to the pressing direction of the bulks at the highest consolidation temperature of 450 °C owing to the presence of homogeneously distributed recrystallized fine grains in the microstructure. However, a little improvement in grain orientations along the perpendicular sections delivered slightly enhanced thermoelectric properties compared to the parallel sections, resulting in the highest figure-of-merit 1.41 × 10−3 K−1 at 450 °C consolidation temperature.