The effect of TiB/sub 2/ addition on the thermoelectric properties of B/sub 4/C ceramics

Abstract

B/sub 4/C-TiB/sub 2/ composites were prepared via hot-pressing. The thermal conductivity, electrical conductivity and Seebeck coefficient of samples containing 0, 12, 16, 20 vol% TiB/sub 2/ are measured from room temperature up to 1200 K. The results show that the electrical conductivity and thermal conductivity increase with TiB/sub 2/ content and that the Seebeck coefficient decreases with TiB/sub 2/ content. The value of dimensionless figure of merit of 12% TiB/sub 2/ sample is always higher than that of 0% TiB/sub 2/ sample in the whole temperature range, and that of 16% TiB/sub 2/ samples is also higher than that of 0% TiB/sub 2/ sample as T<700 K and similar as T>700K, while that of 20% TiB/sub 2/ samples is lower than that of 0% TiB/sub 2/ sample due to its higher thermal conductivities and lower Seebeck coefficients than those of 0% TiB/sub 2/ sample. These results indicate that it is possible to improve the thermoelectric properties of pure materials by selecting an optimum combination of different materials.