Disorder scattering effect on the high-temperature lattice thermal conductivity of TiCoSb-based half-Heusler compounds

The lattice thermal conductivities of TiCoSb-based half-Heusler alloys are presented in the temperature range between 300 and 900 K. A phenomenological model calculation of the high-temperature lattice thermal conductivities of these alloys was derived based on the Klemens-Callaway theory [Phys. Rev. 119, 507 (1960); ibid. 113, 1046 (1959)]. Good agreement was obtained between the calculated and the experimental data for TiCoSb, T'Co0.5Rh0.5Sb, and Ti0.5Zr0.5CoSb. Furthermore, the model predicts that simultaneously isoelectronic alloying on both Ti and Co sublattices could reduce the lattice thermal conductivity, and a kappa(L) value of 0.3 W/m K is predicted for Ti0.5Zr0.5Co0.5Rh0.5Sb at 900 K. (c) 2005 American Institute of Physics.