Thermal expansion and melting temperature of the half-Heusler compounds: MNiSn (M = Ti, Zr, Hf)

Half-Heusler compounds: MNiSn (M = Ti, Zr, Hf) are considered as a candidate of environmentally friendly and low-cost thermoelectric (TE) materials. Although the thermomechanical properties are quite important when utilizing the half-Heusler compounds in TE devices, such properties have been scarcely reported. In the present study, we tried to collect the data of the thermal expansion coefficient and the melting temperature (Tm) of MNiSn. The thermal expansion coefficient was evaluated by means of two methods: the dilatometer measurement and the high temperature X-ray diffraction analysis. The Tm was evaluated from the differential thermal analysis. The relationship between the thermal expansion coefficient and the Tm of the half-Heusler compounds was studied.