Improving the power factor of spark plasma sintered Bi 0,5 Sb 1,5 Te 3 via TiC dispersion

Integrating ceramic particles into the main thermoelectric material is a novel approach to enhance thermoelectric properties. In this work, we fabricated highly dense p-type Bi0,5Sb1,5Te3 thermoelectric materials dispersed with x wt% TiC particles (x = 0, 0.4, 0.6, 0.8) using the melting-solidification followed by spark plasma sintering (SPS) methods. The crystal structures were analyzed using X-ray diffraction (XRD), and surface and cross-sectional microstructures, as well as the presence of TiC particles in the matrix, were systematically investigated through scanning electron microscopy (SEM). The incorporation of TiC into the Bi0,5Sb1,5Te3 alloy resulted in a notable enhancement of electrical conductivity, exceeding 10 % at all range temperatures across all samples. The rise in weighted mobility and grain boundary coefficients are the main factors responsible for this enhancement. Nevertheless, the Seebeck coefficient measurements indicate a reduction in all samples as a result of the n-type semiconductor characteristics of TiC, where the carrier concentration is mostly governed by electrons. As a result, the power factor has improved by around 5 %. Additionally, the Vickers hardness of the Bi0,5Sb1,5Te3/TiC composites exhibited improvement exceeding 15 % compared to the base matrix.