Thermal transport properties of InFeZnO4-YbFeZnO4 solid solutions

Thermal transport properties of In1−xYbxFeZnO4 (x = 0, 0.1, 0.2,…, 0.8, 0.9, 1.0) solid solutions ceramics were investigated, which were synthesized by solid state reaction at 1300 °C (1250 °C for YbFeZnO4) for 30 h. With increasing Yb doping fractions on In site, the solution phase gradually transformed from InFeZnO4 to YbFeZnO4 phase, while the two structures belong to the same YbFe2O4-type structure in the hexagonal R3‾m space group. Due to the point defects scattering, the thermal conductivity of In0.4Yb0.6FeZnO4 reached a minimum value of 1.19 W m−1 K−1 at 1000 °C, which is much lower than the thermal conductivity (∼2.2 W m−1 K−1 at 1000 °C) of 8 wt.% yttria stabilized zirconia (8YSZ) thermal barrier coatings. The present results indicate that In1−xYbxFeZnO4 ceramics are very promising as thermal barrier coatings.