Grain size effects on thermoelectric properties of hot-pressed CoSb/sub 3/
Grain size effects on thermoelectric properties of hot-pressed CoSb/sub 3/
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DOI：
10.1109/ict.1997.667151
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发表时间：
1997-08
期刊：
影响因子：
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通讯作者：
H. Nakagawa;H. Tanaka;A. Kasama;H. Anno;K. Matsubara
中科院分区：
文献类型：
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作者：
H. Nakagawa;H. Tanaka;A. Kasama;H. Anno;K. Matsubara
为了获得高的ZT值，热压CoSb/sub 3/的晶粒尺寸优化是非常重要的。虽然CoSb/sub 3/的单晶具有高的电导率和中等的塞贝克系数，但由于高的热导率，ZT值相对较低。我们试图通过减小晶粒尺寸来降低热压CoSb的热导率。采用Co、Sb原料粉末的机械合金化是降低热压CoSb/sub 3/的晶粒尺寸的有效方法。本文研究了热电性能（霍耳迁移率、塞贝克系数、电导率和热导率）与晶粒尺寸的关系。热压CoSb/sub 3/的热导率随着晶粒尺寸的减小而降低。对于平均晶粒尺寸为0.9 μ m/s的热压材料，在293 K下最终获得4.19 Wm/sup-1/ K/sup-1/的值，其约为单晶的40%。虽然较大的晶粒尺寸是优选的，以获得高的ZT值在293 K，因为更大的载流子迁移率的降低比热导率与减少平均晶粒尺寸，最高的ZT值为0.10，在673 K的样品上获得的平均晶粒尺寸为2.1 /spl μ/m。
To get high ZT values, grain size optimization of hot-pressed CoSb/sub 3/ is very important. Although single crystals of CoSb/sub 3/ have high electrical conductivities and moderate Seebeck coefficients, the ZT values are relatively low because of the high thermal conductivities. We tried to lower the thermal conductivity of hot-pressed CoSb by reducing the grain size. Mechanical alloying of the raw material powders of Co and Sb was the very effective method to reduce the grain size of hot-pressed CoSb/sub 3/. This paper shows the relations between the thermoelectric properties (Hall mobility, Seebeck coefficient, electrical conductivity and thermal conductivity) and the grain size. The thermal conductivity of hot-pressed CoSb/sub 3/ decreased with reducing the grain size. The value of 4.19 Wm/sup -1/ K/sup -1/, which is about 40% of the single crystals, was ultimately obtained at 293 K for the hot-pressed material with an average grain size of 0.9 /spl mu/m. Although the larger grain size is preferable to attain a high ZT value at 293 K, because of the greater decrease of the carrier mobility than the thermal conductivity with reducing the average grain size, the highest ZT value of 0.10 was obtained at 673 K on the sample with an average grain size of 2.1 /spl mu/m.