Thermal properties of RE2AlTaO7 (RE = Gd and Yb) oxides

In the current paper, the synthesis of RE2AlTaO7 (RE = Gd and Yb) oxides was performed through a high-temperature sintering method using Gd2O3, Yb2O3, Al2O3 and Ta2O5 as raw chemicals. The phase-structure, micro-morphology and thermal-physical properties of RE2AlTaO7 (RE = Gd and Yb) oxides were analyzed. The RE2AlTaO7 (RE = Gd and Yb) oxides exhibit single pyrochlore-type crystal-structure. Compared to Yb2AlTaO7, the Gd2AlTaO7 has greater thermal conductivity owning to relatively weaker phonon scattering. Because of higher electro-negativity of Yb, the Yb2AlTaO7 has lower coefficient of thermal expansion than Gd2AlTaO7. The RE2AlTaO7 (RE = Gd and Yb) oxides also exhibit no phase-transition between ambient and 1473 K.