The role of grain boundary scattering in reducing the thermal conductivity of polycrystalline XNiSn (X = Hf, Zr, Ti) half-Heusler alloys.

ABSTRACT: Thermoelectric application of half-Heusler compounds suffers from their fairly high thermal conductivities. Insight into how effective various scattering mechanisms are in reducing the thermal conductivity of fabricated XNiSn compounds (X = Hf, Zr, Ti, and mixtures thereof) is therefore crucial. Here, we show that such insight can be obtained through a concerted theory-experiment comparison of how the lattice thermal conductivity κ _Lat(T) depends on temperature and crystallite size. Comparing theory and experiment for a range of Hf_0.5Zr_0.5NiSn and ZrNiSn samples reported in the literature and in the present paper revealed that grain boundary scattering plays the most important role in bringing down κ _Lat, in particular so for unmixed compounds. O

SUBMITTER: Schrade M 

PROVIDER: S-EPMC5653807 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature