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. (c) 2007 Elsevier B.V. All rights reserved.