High-temperature thermoelectric properties of Ti_x(ZrHf)_0.99-xV_0.01Ni_0.9Pd_0.1Sn_0.99Sb_0.01 half-Heusler alloys

The effect of Ti substitution at the Zr and Hf site on thermoelectric properties of Ti_x(ZrHf)_0.99-xV_0.01Ni_0.9Pd_0.1Sn_0.99Sb_0.01 half-Heusler alloy compounds was investigated by finding the electrical resistivity, Hall effect, Seebeck coefficient, thermal conductivity and using X-ray diffraction. It was shown that substitution of Ti for Zr and Hf leads to a major reduction in the thermal conductivity and an enhancement of the Seebeck coefficient. The observed maximum Seebeck coefficient, minimum electrical resistivity, and minimum thermal conductivity at about 820 K are -206 μV K^-1, 0.71 mΩ cm, and 5.13 W m^-1 K^-1, respectively. In addition, the dimensionless figure of merit is about 0.92 at about 820 K with a Ti content at x = 0.3.