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 (ZTmax) 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 m1/2 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.