Thermoelectric properties of SiC/C composites from wood charcoal by pulse current sintering

SiC/C composites were investigated by sintering a mix of wood charcoal and SiO2 powder (32–45 μm) at 1400, 1600 and 1800 °C under N2 atmosphere with a pulse current sintering method. Thermoelectric properties of SiC/C composites were investigated by measuring the Seebeck coefficient and the electrical and thermal conductivities as a function of heat treatment temperature and reaction time. The Seebeck coefficient showed a p-type to n-type transition at a heat treatment temperature around 1600 °C. The electrical conductivity showed a steady increase with temperature for all three heat treatment temperatures. For the thermal conductivity, the samples heated at 1800 °C showed high values at room temperature which strongly decreased with increase in measurement temperature. In total, thermoelectric properties were improved with an increase in measurement temperature. A maximum in the figure of merit of 3.38 × 10−7 K−1 was reached at 200 °C in the sample heated at 1400 °C for 30 min.