IMPROVING THE POWER FACTOR OF SPARK PLASMA SINTERED Bi0,5Sb1,5Te3 VIA TiC DISPERSION

Abstract

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 Bi_0,5Sb_1,5Te₃ 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 Bi_0,5Sb_1,5Te₃ alloy resulted in a notable enhancement of electrical conductivity, exceeding 10% at all range temperatures across all samples. The rise in mobility and grain boundary coefficients are the main factors responsible for this enhancement. However, the Seebeck coefficient measurements a decrease in all samples due to the n-type semiconductor nature of TiC, where carrier concentration is dominated by electrons. As a result, the power factor has improved by around 5%. Additionally, the Vickers hardness of the Bi_0,5Sb_1,5Te₃/TiC composites exhibited improvement exceeding 15% compared to the base matrix.