Effect of mechanical milling on thermoelectric properties of half-Heusler ZrNiSn0.98Sb0.02 intermetallic compound

Thermoelectric properties of half-Heusler ZrNiSn intermetallic compound were investigated. The partial substitution for Sn site in ZrNiSn by Sb is effective for the reduction of the electrical resistivity, which leads to increase the power factor of the compound. The thermal conductivity for ZrNiSn0.98Sb0.02 can be reduced by the mechanical milling process maintaining the moderate Seebeck coefficient and electrical resistivity. The reduction of the thermal conductivity is ascribed to the enhancement of the phonon scattering accompanied with the minute crystal grains in the milled compounds. As a result, ZrNiSn0.98Sb0.02 with a milling time of 3 h shows a maximum ZT of 0.67 at 573 K.