Single thermite-type combustion synthesis of Fe2VAl for thermoelectric applications from Fe, V2O5 and Al powders

Single thermite-type combustion synthesis (STCS) for synthesizing Heusler alloy Fe2VAl from Fe, V2O5, and Al powders for thermoelectric applications was proposed and investigated, in which the microstructure and the thermoelectric properties of the product were mainly examined. Macroscopically, STCS was successfully carried out to produce metallic product of Fe2VAl in lower part and alumina as slag in upper part. According to SEM observation and FE-EPMA-analyzed, elemental mapping images, the product contained dispersed inclusions of spherical Al2O3 with 0.4 mol% and angulated AlN with 1.0 mol%. In comparison to the reported data on Fe2VAl, the thermal conductivity at room temperature became about half. It could be because of increased phonon scattering due to dispersed AlN&Al2O3 and non-stoichiometry of the product; Fe2.06V1.01Al0.93. As a result, the maximum values for the product were 99.6 μW m−1 K−2 in power factor and 2.19 × 10−3 at 309 K in dimensionless figure of merit.