Fabrication and thermoelectric properties of Yb-doped ZrNiSn half-Heusler alloys  

作　　者：Xiao-Hua Liu Jian He Han-Hui Xie Xin-Bing Zhao Tie-Jun Zhu 

机构地区：[1]State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,P.R.China [2]Department of Physics and Astronomy,Clemson University,South Carolina 29634-0978,USA

出　　处：《International Journal of Smart and Nano Materials》2012年第1期64-71,共8页国际智能和纳米材料杂志（英文）

基　　金：supported by the Nature Science Foundation of China(Grant Nos.51171171 and 50971115);the National Basic Research Program of China(Grant No.2007CB607502);J.H.would like to thank the support by the National Science Foundation of the United States(Grant No.1008073).

摘　　要：Half-Heusler(HH)alloys constitute an important class of materials that exhibit promising potential in high-temperature thermoelectric(TE)power generation.In this work,we synthesized Zr_(1−x)Yb_(x)NiSn(x=0,0.01,0.02,0.04,0.06 and 0.10)HH alloys using a time-efficient levitation melting and spark plasma sintering procedure.X-ray diffraction showed that the samples were predominantly single phased,and that the lattice constant increased systematically with increasing Yb doping ratio.The doping effects of Yb on the thermoelectric properties were studied.It was found that Yb doping consistently decreased the electrical and thermal conductivities.On the other hand,the effects of Yb doping on the Seebeck coefficient were found to be non-monotonic.The magnitude of the Seebeck coefficient(n-type)was increased upon Yb doping up to x=0.02,above which Yb doping introduced notable p-type conduction.As a result,the room-temperature Seebeck coefficient of the x=0.10 sample became positive although the magnitude was not high.The thermoelectric figure of merit,ZT,reached a maximum of∼0.38 at 900 K for the x=0.01 sample.Selective doping on the Ni and Sn sites are necessary to further optimize the TE performance of Zr_(1−x)Yb_(x)NiSn alloys.

关 键 词：half-Heusler alloy thermoelectric power levitation melting spark plasma sintering Yb doping 

分 类 号：TG1[金属学及工艺—金属学]