Effect of substitution for Ni by Co and/or Cu on the thermoelectric properties of half-Heusler ZrNiSn
Effect of substitution for Ni by Co and/or Cu on the thermoelectric properties of half-Heusler ZrNiSn
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DOI：
10.1016/j.jallcom.2004.02.061
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发表时间：
2004-12-28
影响因子：
6.2
通讯作者：
Ito, M
中科院分区：
文献类型：
--
作者：
Katsuyama, S;Matsushima, H;Ito, M
我们合成了半赫斯勒 ZrNiSn 合金，其中 Ni 部分被 Co 和/或 Cu 取代。这种替代通过改变材料的价电子数（VEC）来极大地影响ZrNiSn的热电性能。 ZrNi1-xCoxSn 或 ZrNi1-yCuySn 体系的塞贝克系数和电阻率的行为可以理解为空穴或电子载流子分别随着 x 或 y 的增加而增加的结果。 ZrNi0.98Cu0.02Sn的VEC为18.02，表现出最大的功率因数。我们还合成了ZrNiSn中Ni位被Co和Cu原子取代的样品ZrNi1-x-yCoxCuySn。为了保持最佳的VEC，y-x的值固定为0.02。 ZrNi1-x-yCoxCuySn 的塞贝克系数几乎是恒定的，与 x 和 y 无关。随着x和y的增加，热导率降低，而电阻率增加。热导率的降低和电阻率的增加分别归因于伴随取代的声子和传导载流子的散射的增强。结果，ZrNi0.98Cu0.02Sn在570 K时显示出约0.22的最大无量纲品质因数，这比ZrNiSn大一些。 (C) 2004 Elsevier B.V. 保留所有权利。
We have synthesized the half-Heusler ZrNiSn alloys where the Ni is partially substituted by Co and/or Cu. Such substitution much affects the thermoelectric properties of ZrNiSn by changing the valence electron count (VEC) of the material. The behaviors in the Seebeck coefficient and electrical resistivity for ZrNi1-xCoxSn or ZrNi1-yCuySn system can be understood as the result of the increase in the hole or electron carrier with an increase of x or y, respectively. ZrNi0.98Cu0.02Sn, whose VEC is 18.02, showed a maximum power factor. We have also synthesized the samples whose Ni site of ZrNiSn is substituted by both Co and Cu atoms, ZrNi1-x-yCoxCuySn. In order to maintain the optimum VEC, the value of y-x is fixed at 0.02. The Seebeck coefficient of ZrNi1-x-yCoxCuySn is almost constant independent of x and y. With increase of x and y, the thermal conductivity decreases, while the electrical resistivity increases. The decrease of the thermal conductivity and the increase of the electrical resistivity are ascribed to the enhancement of the scattering of the phonon and the conduction carrier accompanied with the substitution, respectively. As a result, ZrNi0.98Cu0.02Sn shows a maximum dimensionless figure of merit of about 0.22 at 570 K, which is some larger than that of ZrNiSn. (C) 2004 Elsevier B.V. All rights reserved.