The high temperature thermoelectric performances of Zr0.5Hf0.5Ni0.8Pd0.2Sn0.99Sb0.01 alloy with nanophase inclusions

The Zr0.5Hf0.5Ni0.8Pd0.2Sn0.99Sb0.01/ZrO2 nanocomposites have been prepared by spark plasma sintering technique. The thermoelectric properties were measured in the temperature range of 300-900 K. Thermal conductivity for the nanocomposites is considerably reduced, because the nanophase scatters the thermal phonons which transport most of the heat in the ZrNiSn-based alloy. Seebeck coefficient for the nanocomposites is enhanced due to the potential barrier scattering. The dimensionless figure of merit ZT is improved, with ZT approximate to 0.75 at 800 K for the samples containing 9 vol % ZrO2 nanoinclusions. The results obtained suggest that considerable improvements in the thermoelectric figure of merit may be obtainable by inducing appropriate nanoinclusions into the matrix.