Abstract

Materials based on CeO₂-Sm₂O₃ system are promising candidates for a wide range of applications, but the phase relationship has not been studied systematically previously. To address this challenge, the subsection of the phase diagram for 600, 1100 and 1500 °C has been elucidated. Samples of different compositions have been prepared from nitrate acid solutions using conventional ceramic techniques; evaporation, drying, and calcinations. The phase relations in the binary CeO₂-Sm₂O₃ system at 600- 1500 °C in air were studied from the heat treated samples using X-ray diffraction analysis and in the overall concentration range. It was established that in the binary CeO₂-Sm₂O₃ system there exist fields of solid solutions based on monoclinic (B) modification of Sm₂O₃, cubic (C) modification of Sm₂O₃ and cubic modification of CeO₂ with fluorite-type structure (F). The systematic study that covered whole composition range excluded formation of new phases. The refined lattice parameters of the unit cells and the boundaries of the homogeneity fields for solid solutions were determined.

Keywords: Phase equilibria; Ceria; Samaria; Solid solutions; Lattice parameters