Improved thermoelectric properties of spark plasma sintered B4C with SiC-segregated network structures

Abstract

Different amounts of SiC particles were coated on spray-dried B4C granules with a simple dry particle coating method, then spark plasma sintered to form B4C with SiC-segregated network structures in order to improve the thermoelectric performance of B4C. This tailored network structure simultaneously increased the Seebeck coefficient by carrier scattering and decreased thermal conductivity by grain boundary scattering with a minimal decrease in electrical conductivity. A continuous SiC-segregated network structure was obtained with higher additions of SiC, whereas a discontinuous SiC-segregated network structure was obtained with low amounts of SiC addition. A maximum ZT of 0.12 at 923 K was achieved with a low amount of 2 vol% SiC addition, improving the ZT of monolithic B4C by an impressive ≈ 230%.