Thermoelectric properties of p-type Fe2(V1-x-yTi xTay)Al alloys

Abstract

We report on the temperature dependence of the electrical resistivity and the Seebeck coefficient for the p-type Fe2(V1-x-y Ti xTay) Al alloys with compositions 0≤x≤0.10 and 0≤y≤0.10, in addition to the composition dependence of the thermal conductivity at room temperature. While Fe2VAl (x = 0, y = 0) exhibits a semiconductor-like behavior in the electrical resistivity, a slight doping of Ti and Ta causes a significant decrease in the resistivity at low temperature and a large enhancement in the Seebeck coefficient, reaching 90 nV/K for x = 0.03 and y = 0.10. The power factor is found to be substantially larger than that for the p-type Fe2 (V1-x,Tix) Al alloys so far reported. Although the thermal conductivity for Fe2 (V1-x,Tix) Al remains in the range of 24-28 W/mK for 0≤x≤0.10, it decreases significantly with the Ta substitution, reaching 11-12 W/mK for 0≤x≤0.10 and y = 0.10. We conclude that doping of heavier atoms such as Ta reduces more effectively the lattice thermal conductivity. © 2008 The Japan Institute of Metals.