The effect of preparation method on transport and thermoelectric properties of Hf1.75Ti0.25FeNiSb2-xInx double half-Heusler alloys

The experimental investigations focus on the thermoelectric and structural properties of newly synthesized Hf1.75Ti0.25FeNiSb2-xInx (x = 0.05 and 0.1) alloys, which are double half-Heusler alloys. The objective is to determine the impact of altering the production method from ball milling to melt spinning. Two of the samples were synthesized utilizing distinct techniques: melt spinning, arc melting, and spark plasma sintering. In contrast, the other two samples were created by ball milling instead of melt spinning. The X-ray diffraction technique was used to determine the crystal structures of all the samples. The face-centered cubic structure was identified as the primary crystallization phase for all the samples. The manufactured samples were determined to be uniform. Thermoelectric properties were investigated across a wide temperature range of 300 to 870 K. The thermal properties of the ball-milled samples were superior to those of the melt-spun samples due to the presence of larger pores, which enhanced phonon scattering. The Hf1.75Ti0.25FeNiSb1.9In0.1 alloy, which was subjected to ball milling, achieved the greatest thermoelectric figure of merit value of 0.38 at a temperature of 870 K.