Thermoelectric properties of spark plasma sintered SiC

The SiC-sintered materials were fabricated by SPS (Spark Plasma Sintering) for thermoelectric energy conversion. The n- and p-type conductions are controlled by doping Si3N4 and B4C as the source materials of N and B, respectively. The observed density of the sintered materials is larger than 70% of the calculated density (3.21 g.cm(-3)) and the doping is effective to attain the increased densities., The crystal structures of sintered materials are cubic (beta-SiC type) and hexagonal(6H) on doping of Si3N4 and B4C, respectively The electrical resistivity decreases with increased amount of the dopant. The carrier concentration at 5wt%-doping is in the order of magnitude of 10(25) m(-3) in the temperature range from 673 to 1073K, where the large power factor of 4.0 mWm(-1)K(-2) resulted for n-type. The results indicate that SPS is effective for improvement of thermoelectric properties of SiC sintered materials.