Improved thermoelectric properties of SiC with TiC segregated network structure

A TiC segregated network structure (SNS) approach was utilised to improve the thermoelectric properties of SiC. Different amounts of TiC particles were dry coated on SiC granules to form electrically conductive SNS; then the powder mixtures were spark plasma sintered at 2200°C. The TiC-SNS simultaneously increased the electrical and decreased thermal conductivity of SiC but adversely affected the Seebeck coefficient. By adding 10 vol% TiC, an ≈ 800% increase in electrical conductivity and a ≈ 50% decrease in thermal conductivity were achieved, but the Seebeck coefficient deteriorated due to the metallic nature of the material. A maximum ZT of 5.04 × 10−3 was achieved at 923 K, by limiting the Seebeck coefficient's reduction by optimising TiC content to 1.5 vol% while simultaneously increasing the electrical conductivity by ≈ 100% and reducing thermal conductivity by ≈ 40%. This ZT value is almost 90% higher than any value recorded in the literature for SiC.