Phase composition and thermophysical performances for (Sm1-xYbx)3TaO7 compounds

The (Sm1-xYbx)3TaO7 compounds were prepared using high-temperature calcining technology to evaluate the impact of Yb2O3 on the crystal-type and thermal-physical performances for Sm3TaO7. Final analytical conclusions show that the synthesised compounds have a sole pyrochlore or fluorite crystal structure, and the lattice variation from pyrochlore to fluorite is found with an increase in Yb2O3 fraction. Owing to the phonon scattering caused by substituting cation and disorder atomic arrangement, the heat insulation ability of (Sm1-xYbx)3TaO7 oxides is improved, which meets the requirements for thermal barrier coatings. The synthesised (Sm1-xYbx)3TaO7 oxides also present relatively high linear thermal expansion coefficients owing to the combined influence of ionic radius and crystal lattice energy. The addition of Yb2O3 also improves the crystal constancy until 1200 °C.