Study of the microstructure influence on the transport properties of Bi86.5Sb13.5 polycrystalline alloy

This study is focused on the investigation of the transport properties of Bi86.5Sb13.5 polycrystalline alloys. Bulk materials were prepared by cold pressing ultrafine powders of alloy and by annealing the resulting pellets. Special care was taken to avoid contamination of the powders. Starting with powders of average grain size of 0.06 mm bulk semi-conducting sample with mean grain size resp. of 0.1, 0.8, 2.5 and 200 mm were obtained. The influence of the grain size on both electrical resistivity, thermal conductivity, thermoelectric power, thermoelectric figure of merit is presented within the range 80-330 K. The thermoelectric properties are discussed and compared with those of single crystals presented in previous studies. 18 refs.