バイモーダルな結晶粒径分布を持つCoSb<sub>3 </sub>焼結体の熱電特性

Abstract

In the composite composed of high electrical conductivity and low electrical conductivity materials the percolation phenomenon is often observed; the electrical conductivity of the composite is maintained low before the volume fraction of the high electrical conductivity component reaches at a specific value (percolation threshold), and over the percolation threshold, the electrical conductivity of the composite rapidly increases. On the other hand, such percolation phenomenon is not generally observed in the thermal conduction. We have pointed out a possibility of the enhancement of the performance of thermoelectric materials by the application of the percolation phenomenon. We have synthesized the sintered skutterudite CoSb3 composed of coarse and fine crystal grains (with a bimodal distribution of crystal grains) and investigated its thermoelectric properties. The experimental result was discussed from the point of view of the percolation theory.