Preparation and properties of SiC/β-Zn₄Sb₃ thermoelectric composites

SiC/β-Zn₄Sb₃ thermoelectric composites with different contents of SiC nanoparticles were prepared by a process of vacuum melting and quenching combined with plasma activated sintering (PAS). The phase compositions and microstructures of the materials were characterized by X-ray diffraction and scanning electron microscopy. The resistivity, the Seebeck coefficient and the thermal conductivity were measured at 300-700 K. The results show that the composite is composed of SiC and β-Zn₄Sb₃ phases, and there is no phase transition in the PAS process. The SiC nanoparticles are randomly distributed in β-Zn₄Sb₃ matrix. The electrical transport properties of the composite indicate that the resistivity increases, and the Seebeck coefficient firstly increases and then decreases with the increase of SiC content. When the content of SiC is 1.0%, the thermoelectric figure of merit (ZT) is 1.03 at 673 K, which is increased by 37%, compared to that of single phase β-Zn₄Sb₃.