Improvement Mechanism of Thermoelectric Materials by Dispersion of Fine Particles.

The performance of The thermoelectric materials is represented by The figure of merit ZZ=α D12 e D1/ρκ, where α is Seebeck coefficient, ρ is electrical resistivity和κ is thermal conductivity. In order to obtain a high figure of merit，a large Seebeck coefficient and low electrical resistivity is requiredas as a low thermal conductivity. The effects of dispersion of fine particles on Thethermoelectric propeties are investigated in this study.The results obtained are as follows(1)Thermoelectric materials (β-FeSi - D22 - D2和CoSb - D23 - D2) with dispersion of fine particlesare obtained by mechanical alloying (MA) and hot-pressing method. (2) β-FeSi d - 22 d - 2 withultra-fine SiC dispersion was obtained by MA of FeSi D22 D2Si and C powders. The performance was markedly improved by decreasing The thermal conductivity. (3)Electrical resitivity and thermal conductivity of CoSb D23 - 2 were markedly decreased by thedispersion of FeSb D22 - D2 and NiSb D22 - D2 particles with low resistivity. (4) Hall effectmeasurements revealed that dispersion of second phases differently affects the thermoelectricproperties of n-type and p-type materials due to the electronic interaction between the matrix andthe second phases

The performance of the thermoelectric materials is represented by the figure of merit Z : Z=αィイD12ィエD1/ρκ, where α is Seebeck coefficient, ρ is electrical resistivity, and κ is thermal conductivity. In order to obtain a high figure of merit, a large Seebeck coefficient and low electrical resistivity is required, as well as a low thermal conductivity. The effects of dispersion of fine particles on the thermoelectric propeties are investigated in this study.The results obtained are as follows :(1)Thermoelectric materials (β-FeSiィイD22ィエD2 and CoSbィイD23ィエD2) with dispersion of fine particles are obtained by mechanical alloying (MA) and hot-pressing method. (2) β-FeSiィイD22ィエD2 with ultra-fine SiC dispersion was obtained by MA of FeSiィイD22ィエD2, Si and C powders. The performance was markedly improved by decreasing the thermal conductivity. (3) Electrical resitivity and thermal conductivity of CoSbィイD23ィエD2 were markedly decreased by the dispersion of FeSbィイD22ィエD2 and NiSbィイD22ィエD2 particles with low resistivity. (4) Hall effect measurements revealed that dispersion of second phases differently affects the thermoelectric properties of n-type and p-type materials due to the electronic interaction between the matrix and the second phases.