Microwave synthesis and enhancement of power factors of Hf_xTi_1−xNiSn

A series of Hf-doped Hf_xTi_1−xNiSn (x = 0.1, 0.2, and 0.3)bulk samples are fabricated by microwave synthesis for 5 minutes and microwave sintering for 20 min. The phase composition and microstructure of the samples are characterized by X-ray diffraction (XRD), laser confocal Raman scattering (LCRS), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM). The Seebeck coefficient, electrical resistivity, and thermal diffusivity are determined and the effects of microwave heating and impurities on the microstructure and thermoelectric properties are investigated and discussed. The largest power factor of 3475 μW m⁻¹ K⁻² and maximum dimensionless thermoelectric figure of merit of 0.41 are achieved from Hf_0.1Ti _0.9 NiSn.