Effects of Nano-a-Al_2O_3 Dispersion on the Thermoelectric and Mechanical Properties of CoSb_3 Composites

摘要

Nano-α-Al_2O_3/CoSb_3 composites with different α-Al_2O_3 contents were prepared by spark plasma sintering. The effects of α-Al_2O_3 addition on the microstructure, the thermoelectric properties, and the mechanical properties were studied in this article. It is found that α-Al_2O_3 nanoparticles locate mainly at grain boundaries of the matrix. The dispersed particles decrease both the electrical conductivity and the thermal conductivity, but make the Seebeck coefficient increase. The dimensionless figure of merit is nearly unchanged by the dispersion. However, the introduction of nano-α-Al_2O_3 is very effective in improving the mechanical performance of the composites. The compressive strength and flexural strength of the 1.0 wt.% nano-α-Al_2O_3 dispersed samples are improved by 42.7 and 52.0%, respectively, compared with the non-dispersed samples.