Enhanced thermoelectric properties of Nb-doped TiCoSb Half-Heusler alloys prepared by microwave method
Along with the long preparation cycle time and high cost of conventional preparation methods,the inherent high thermal conductivity of TiCoSb Half-Heusler alloy limited its commercial application.Herein,Ti1-xNbxCoSb Half-Heusler alloys with low thermal conductivity were successfully prepared by microwave synthesis combined with rapid hot-pressing sintering,which substantially shortened the preparation cycle and increased the density of TiCoSb Half-Heusler alloys.Furthermore,we studied the effects of Nb substitution at Ti sites on the phase composition,composition distribution,and thermoelectric transport properties of Ti1-xNbx CoSb Half-Heusler thermoelectric materials.Additionally,the figure of merit(ZT)of Ti1-xNbx CoSb samples were considerably optimized under the combined effects of increasing power factor and decreasing lattice thermal conductivity.The results showed that the Ti0 93 Nb0 07CoSb sample had a maximum ZT of 0.1 at 725 K,which was two orders of magnitude higher than that of the TiCoSb sample prepared by the same process.
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