LAUSR

Abstract The preparation of half-Heusler thermoelectric bulk is complex and time-consuming. In the present work, Sb doped TiNiSbxSn1−x bulks (x=0.01, 0.02, 0.03 and 0.04) were prepared via cold press forming, microwave synthesis and sintering in vacuumed sealed quartz in a few minutes. The microstructures of samples were characterized by using X-ray diffractometer (XRD) and scanning electron microscopy (SEM) techniques. The thermoelectric properties i.e. Seebeck coefficient (S), electrical resistivity (ρ) and thermal conductivity (κ) were measured on Seebeck coefficient/resistance analysis system (S/RAs) and laser flash thermal analyzer (LFT). The results show that high purity single phase was obtained after microwave sintering. The point defects came from Sb doping and the in-suit nanostructures attributed to microwave sintering process were found to lead to special microstructure. The variation trends of S, ρ, κ with temperature were analyzed. The influences of Sb doping to electrical and thermal properties were discussed. The electrical resistivity was decreased by ~84% at the cost of decreasing the Seebeck coefficient by ~25–30%. The maximum power factor of 2560 μWm−1K−2 was achieved at 673 K. The lattice and total thermal conductivities are merely 1.1–1.3 and 3.8–4.0 Wm−1K−1 respectively. The thermoelectric figure of merit for TiNiSb0.03Sn0.97 was enhanced from 0.30 (773 K) to 0.44 (673 K and 723 K) when compared to that of non-doped TiNiSn.