Phase equilibria in the La2O3-Fe2O3-Nd2O3 system at 1400 °С

Phase equilibria in the La 2 O 3 –Fe 2 O 3 –Nd 2 O 3 ternary system at 1400 °C were investigated across the entire concentration range using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). Samples were synthesized via nitrate decomposition and annealed at 1400 °C for 100 h in air. The isothermal section at 1400 °C is characterized by two single-phase regions, consisting of the A-type (La,Nd)2O3 and the orthorhombic R-phase (La 1-x Nd x FeO 3 ) solid solutions, and two-phase regions (A + R and Fe 2 O 3 + R). The homogeneity range of the R-phase solid solution extends from 47 to 49 mol. % Fe 2 O 3 at 1400 °C. Solubility limits were established, and the concentration dependence of the unit-cell parameters for the constituent phases was determined.