Comparison of different sintering methods of Pb1−xCrxTe thermoelectric nanocomposites doped with iodine

Abstract

N-type PbTe polycrystals were fabricated by the Bridgman method. Subsequently, the materials were pulverized in a planetary ball mill for 15h, pressed and sintered. In this paper we compare two sintering techniques: cold pressing followed by the sintering in a furnace (CPS) and the spark plasma sintering (SPS). The electrical and thermoelectric measurements were conducted for both materials (CPS and SPS) and the results are presented and discussed in the paper. Maximal ZT values of 0.2 and 0.45 were obtained for the CPS and SPS materials, respectively. Additionally, SEM and EDX analyses were performed. To determine the obtained crystallites size, the X-ray diffraction measurements were carried out. The obtained results show that the significant reduction in particle size may be obtained by the milling procedure - from a few milimeters in the polycrystalline material to a few tens of nanometers for the powdered one.