Authors: Rizwan Akram Qiang Zhang Dongwang Yang Yun Zheng Yonggao Yan Xianli Su Xinfeng Tang
Publish Date: 2015/06/23
Volume: 44, Issue: 10, Pages: 3563-3570
Abstract
The effect of La doping on ZrNiSn halfHeusler HH compound has been studied to explore the composition variation and structural modifications for improvement of its thermoelectric performance A series of La x Zr1−x NiSn x = 0 0005 001 0015 002 003 alloys were prepared by induction melting combined with plasmaactivated sintering Structural analysis using xray diffraction XRD scanning electron microscopy SEM and transmission electron microscopy TEM confirmed the resulting material to be a composite of HH NiZr and La3Sn4type phases The volume fraction for the phases other than HH ranged from 15 to 25 with increasing La content as estimated by Rietveld analysis The solubility of La in ZrNiSn is estimated to be 15 Point defects may play a significant role in carrier and phonon transport Interestingly the thermoelectric transport properties exhibited a considerable increase in electrical conductivity σ with La doping and a significant drop in thermal conductivity κ leading to a thermoelectric figure of merit ZT of 053 at 923 K representing an improvement of about 37 compared with the undoped sample
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