The Ce-La-O system was investigated via experiments and thermodynamic modeling. A series of CeO2-LaO1.5 mixtures were prepared by co-precipitation technique and examined by X-ray diffraction. Mutual solubilities between LaO1.5 and CeO2 at 1273 K were determined. Using the new experimental data together with literature information, a set of self-consistent thermodynamic parameters for the CeO2-LaO1.5 system were optimized. Combined with thermodynamic descriptions of Ce-O and La-O systems from literature, several property diagrams of Ce-La-O system were calculated and used to explain oxidation process of the Ce-La alloys. The fluorite phase is the unique oxidation products for most of the Ce-La alloys.
