High performance properties of sintered Bi2Te3-based thermoelectric material

Bi/sub 2/Te/sub 3/-based thermoelectric materials have been studied for fabrication parameters and orientation effects. The powder particle sizes were less than 150 /spl mu/m and the mixtured grain sizes after sintering were observed in scanning electron microscope. As the results, electrical resistivity was 40% lower by reducing powders before pressing, and cold isostatic press took away the layer structures formed with pressing. The direction to the pressing and the measurements indicated lower resistivities (30-60%) for both p- and nBi/sub 2/Te/sub 3/, then Z values were 2.05 and 2.23 K/sup -1/ for those types, respectively. It should be notified that the composites of large and small grains will mitigate an enhancement of electrical resistivity and reduce thermal conductivity in a sintered specimen.