Thermoelectric properties of carbide ceramics:a comparative analysis of thermoelectric properties of B4C, SiC and TiC

Abstract

Common high-temperature thermoelectric materials' expensive and rare element contents create a need to develop readily available and cost-effective materials such as carbides, as they have naturally abundant constituents, low costs, and good high-temperature performance. Although there are published research results on the thermoelectric properties of B₄C and SiC, they vary widely in production and characterization methods, hence the results. To efficiently compare these materials and initiate a starting point for material selection for developing thermoelectric ceramics and composites as alternatives to toxic and costly common high-temperature thermoelectric materials, B₄C, SiC, and TiC were spark plasma sintered under similar conditions with different sintering temperatures due to the different characteristics of the materials. Their thermoelectric properties were analyzed between 323 and 923 K and compared. Thermoelectric properties of TiC were investigated in detail for the first time. The results demonstrated that SiC has a high Seebeck coefficient (564.4 µV/K), low electrical (602.1 S/m), and high thermal conductivity (65.8 W/mK), B₄C has high electrical (6974.8 S/m) and low thermal conductivity (12.4 W/mK), and relatively high Seebeck coefficient (269.5 µV/K). In contrast, TiC has metallic electrical (1.3 × 10⁶ S/m) and relatively low thermal conductivities (32.8 W/mK) while a very low Seebeck coefficient (-9.9 µV/K).