Effect of Nb substitution for V on the thermoelectric properties of Fe2VAl

In order to clarify the substitution effect of Nb for V on the thermoelectric properties of Heusler-type Fe2VAl, we prepared the polycrystalline samples of Fe2V1-xNbxAl (x = 0, 0.05, 0.1, and 0.2) and the electrical resistivity (rho), Seebeck coefficient (S), and thermal conductivity (K) were investigated. The samples with x = 0 and 0.05 were the Heusler-type single phase, while other samples contained a small amount of impurity phases. The Fe2V0.95Nb0.05Al and the Fe2V0.9Nb0.1 Al samples as well as the Fe2VAl sample exhibited relatively high power factor (S-2 rho(-1)) values (>10(-3) W m(-1) K-2 at around room temperature), while that of the Fe2V0.8Nb0.2 Al sample was fairly low. The Nb-substituted Fe2VAl samples indicated lower K values than that of the Fe2VAl sample, indicating that the effective phonon scattering due to the fluctuation effects between V and Nb occurred in the present system. (C) 2009 Elsevier B.V. All rights reserved.