Fabrication of large-scale p-type 75%Sb2Te3-25%Bi2Te3 thermoelectric materials by gas atomization and hot isostatic pressing

For economic viability of thermoelectric modules, issues of scalability and sturdiness to drive down production and manufacturing cost must be adequately addressed. In this study, we report a large-scale production of 3 Kg/batch of 75%Sb2Te3-25%Bi2Te3 powder by gas atomization. The as-produced large-scale atomized powder was subsequently sintered by hot isostatic pressing (HIP) at two different temperatures. The microstructure of the HIPed fracture surface reveals a transgranular mode of fracture in the basal plane of the grains perpendicular to the contact surface. The texture analysis showed that grains were randomly distributed and indicating no preferred alignment in any direction. The sample HIPed at 450 degrees C shows the highest electrical conductivity of 1350 Omega(-1) cm(-1) at room temperature due to their high carrier mobility. The highest ZT of 1.15 at 375 K was observed for the sample HIPed at 450 degrees C owing to their high electrical conductivity, and reasonable low thermal conductivity.