The effect of phase-segregated Heusler TiNi 2 Sn on high temperature thermoelectric properties of bulk half-Heusler TiNiSn has been studied. In samples expressed by the composition TiNi 1+x Sn, a significant decrease in thermal conductivity (between 10% and 30%) is observed for two-phase TiNi 1.15 Sn, despite the second-phase particles existing at the micrometer scale; a 50 increase in the electrical conductivity is also measured. These result in a maximum figure of merit, ZT, of 0.44 at 800 K, which is 25% greater than is observed for the x = 0 sample. Density functional calculations of TiNiSn and TiNi 2 Sn suggest that the latter should deplete carriers at 0 K.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)