Thermoelectric performance of P-type Bi85Sb15-xSnx alloys prepared by mechanical alloying and pressureless sintering at low temperatures

In the present study, the Bi85Sb15-xSnx (x=0, 1, 2, 3) thermoelectric materials have been fabricated through mechanical alloying followed by pressureless sintering. The phase composition and the microstructure were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. Electrical conductivity, Seebeck coefficient and thermal conductivity were measured in the temperature range of 77 similar to 300 K. The electrical conductivity was characterized by using four-probe method. The Seebeck coefficient was determined from measured temperature and electric potential difference between the two ends of the bar-shape specimen. The thermal conductivity was measured by means of a heat and sink steady state method. Then the power factor and ZT were calculated according to the measurement values. The results showed that the Sn-doped samples changed from n-type to p-type at low temperature. A maximum power factor of 1.67 x10(-3)W/mK(2) and a minimum thermal conductivity of 1.8 W/mK were obtained. The optimum ZT value of 0.15 was obtained at 300 K. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Chinese Materials Research Society Open access under CC BY-NC-ND license.