Samples of the CeO2–TiO2–Gd2O3 system were synthesized by the ceramic method, which correspond to the secant in the triangle of compositions with CeO2 concentrations from 10 to 90 mol % and a ratio of mole fractions of TiO2 : Gd2O3 of 1 : 1. The phase composition of the obtained samples was determined by X-ray diffractometry. The qualitative and quantitative composition of vapor over the CeO2–TiO2–Gd2O3 system was determined for the samples in the temperature range of 2100–2200 K. The activity of cerium dioxide in the studied concentration range is characterized by a slight negative deviation from the ideal behavior.
Shugurov et al. (Sun,) studied this question.