Thermoelectric and mechanical properties of nano-SiC-dispersed Bi₂Te₃ fabricated by mechanical alloying and spark plasma sintering

Highly dense n-type Bi₂Te₃ dispersed with x vol% nano-SiC particles (x = 0, 0.1, 0.5, 1.0) thermoelectric materials were fabricated by mechanical alloying (MA) and spark plasma sintering (SPS) method. The effects of nano-SiC addition on the thermoelectric and mechanical properties were studied. Compared with Bi₂Te₃ matrix, Bi₂Te₃ materials dispersed with nano-SiC show increased Seebeck coefficient, decreased electrical conductivity, and reduced thermal conductivity as well in the measured temperature range of 323-523 K. The maximum dimensionless figure of merit (ZT_max) was improved from 0.99 for Bi₂Te₃ sample to 1.04 for 0.1 vol% SiC dispersed Bi₂Te₃ sample at 423 K. The Vickers hardness increased linearly from 0.62 to 0.79 GPa as 1.0 vol% SiC was added. The highest fracture toughness of 1.34 MPa m^1/2 was obtained for 0.1 vol% SiC addition, and the highest Young's modulus of 42.7 GPa was obtained for 0.5 vol% SiC added sample.