Ti1－x(Hf0.919Zr0.081)xNiSn的制备及热电性能

采用固相反应法合成了单相的Ti_1-x(Hf_0.919Zr_0.081) _xNiSn (x＝0.00—0.15)，并用放电等离子烧结方法制备出密实块体材料. 研究 了Hf和Zr同时在Ti位上的等电子合金化对Ti基半Heusler化合物热电性能的影响规律. 结果 表明：少量的Hf和微量的Zr在Ti位上的等电子合金化，显著地降低了体系的热导率κ，同时 显著地提高了体系的Seebeck系数α. 组成为Ti_{0.85关键词： 半Heusler 固相反应 热电性能}

Preparation and thermoelectric properties of Ti1-x(Hf0919Zr0081)xNiSn

Single-phase Ti_1-x(Hf_0.919Zr_0.081)_xN iSn (x＝0.00—0.15) compounds were synthesized by solid-state reaction and high- density polycrystalline bulk material was prepared by spark plasma sintering (SP S). The effect of Hf and Zr substitution for Ti on the thermoelectric propertie s of TiNiSn half-Heusler compounds were investigated. It was shown that the subs titution of a small amount Hf and trace Zr for Ti resulted in significant reduct ion of the thermal conductivity and remarkable enhancement of the Seebeck coeff icient. As a result, the dimensionless figure of merit ZT of Ti_0.85(H f_0.919Zr_0.081)_0.15NiSn reached a high maximum v alue of 0.56 at 700K and the enhancement of ZT was 190%—310% at the same temper ature compared with ternary TiNiSn compounds.