Effect of Rare-earth Doping on the Thermoelectric Properties of the Tin-based Half-Heusler Alloys

Abstract

Intermetallic compounds Zr1-xLaxNiSn(x = 0.05,0.1,0.15,0.2,0.3,0.4) and Zr0.98R0.02NiSn0.98X0.02(R = La,Ce;X=Sb,Bi) were synthesized using arc melting and spark plasma sintering(SPS) techniques.The changes of their crystal structures were analyzed by using X-ray diffractometer.Thermoelectric properties were evaluated in the temperature range of 300 to 925 K.For x≤0.15,single-phase samples can be obtained.With x 0.15,a non-half-heusler phase formed.The content of the second phase increases with x.For the samples with x≤0.15,rare-earth doping can effectively reduce the thermal conductivity while keeping good electrical transport.The maximum value of ZT was obtained in Zr0.98La0.02NiSn0.98Sb0.02,which reaches 0.5 at 575K.