Preparation and properties of Nano-SiC dispersed Bi₂Te₃ thermoelectric materials

Nano-SiC (30 nm) dispersed Bi₂Te₃ alloys were fabricated by mechanical alloying (MA) and spark plasma sintering (SPS) to enhance thermoelectric and mechanical properties with special emphasis on the effect of nano-SiC content. The powders of Bi2Te3 dispersed with nano-SiC were firstly synthesized by MA and then consolidated by SPS. The XRD results indicated that Bi₂Te₃ alloys were synthesized successfully. The grain size of Bi₂Te₃ decreased with increasing SiC content, suggested that the dispersion of nano-SiC particles effectively suppressed the grain growth of Bi₂Te₃. When a small amount of nano-SiC (<1.0 vol%) was added in Bi₂Te₃ alloys, the electrical conductivity decreased slightly but the Seebeck coefficient increased. The maximum values of Seebeck coefficient and power factor were obtained as 0.1 vol% SiC was added. The Vickers hardness was also improved by adding nano-SiC. The addition of a small amount of nano-SiC is effective to enhance both the electrical and mechanical properties of Bi₂Te₃ alloys.