Phase Equilibrium in the Ternary CeО<sub>2</sub>-La<sub>2</sub>O<sub>3</sub>-Yb<sub>2</sub>O<sub>3</sub> System at 1500 °С

Abstract

Materials based on cerium oxides and REE are perspective for use in medicine, energy and mechanical engineering due to the uniqueness of their authorities. Stationary system diagrams are the physicochemical basis for the creation of such materials as solid electrolytes for fuel comics, oxygen gas sensors, catalyst carriers, protected coatings for alloys, etc. In this work, phase equilibria and structural transformations in the system CeO2-La2O3-Yb2O3 at a temperature of 1500 oС in all international concentrations are investigated by the methods of microstistructural and X - ray phase analysis. It is established that in the triple system CeO2-La2O3-Yb2O3 fields of solid solutions based on cubic (F) modification of the structure of the structure of fluorite CeO2, monoclinic (B) and cubic (C) modification of Yb2O3 and hexagonal (A) modification of La2O3 (R) are used, which crystallizes in a Perovski-type structure with rhombic curvatures. It was found that the rarefaction of CeO2 in the crystal lattice of the ordered phase with the structure of the perovskite type LaYbO3 (R) is ~ 3 mol. %. Isothermal review of the state diagram of the systems CeO2-La2O3-Yb2O3 at reveals the presence of two three-phase (F + C + R), (A + R + F) and five two-phase (A + F), (A + R), (R + C), (F + R), (F + C) regions.