Thermoelectric properties of mechanically alloyed Bi–Sb alloys

Abstract.

Homogeneous polycrystalline Bi_100-xSb_x (x=12, 15, 22) alloys were synthesized by mechanical alloying. The transport coefficients (electrical resistivity, thermal conductivity, and thermopower) were measured, in the 77–300 K temperature range, on samples consolidated either by sintering or extrusion. The thermoelectric figure of merit was deduced from the three coefficients. The temperature dependences are discussed as a function of the alloys’ microstructures taking into account the qualitative effect of potential barriers. Extrusion leads to better performing thermoelectric materials than does sintering. The highest figure of merit is reached for temperatures around 150 K, a temperature at which no reliable thermoelectric material of long service life is available until now.