Effects of composition and preferred orientation on microstructure and thermoelectric properties of p-type (BixSb(1-x))2Te3 alloys

In this investigation, p-type (BixSb(1-x))(2)Te-3 alloys having x-0.15, 0.20 and 0.25 were prepared by mechanical alloying (MA), cold pressing and sintering. Phases, orientation and microstructures of the samples obtained were investigated using XRD and SEM. Thermoelectric properties of the samples with the different compositions were characterized and compared. Electrical conductivities, thermal conductivities, Seebeck coefficients and figures of merit (ZT) were affected by composition and preferred orientation. Increasing Bi content, i.e. decreasing Sb content, was found to improve the thermoelectric properties where the best thermoelectric properties among many conditions were obtained from the Bi0.5Sb1.5Te3 compound of which preferred orientation was found on a fracture surface parallel to the compressing direction during cold pressing process. (C) 2010 Elsevier B. V. All rights reserved.