Reevaluation of phase relations in the chemical system neodymium lutetium oxide NdLuO3

The phase relations in the system with the overall chemistry Nd2O3:Lu2O3 around 1:1 were investigated by x‐ray diffraction (XRD) of annealed powders and by differential thermal analysis (DTA). A mixture of rare earth oxide solid solutions in the cubic C and in the monoclinic B rare earth oxide structure was determined in the temperature range 1200 to 1650 °C. The C‐phase is dominated by Lu content while the B‐phase is Nd rich. With rising annealing temperature, the portion of Nd in the C‐phase is increased and lowered for the B‐phase. Different facilitation possibilities for P‐NdLuO3 perovskite formation were discussed and examined but no evidence for stability of this phase could be found experimentally. Two thermal signals of phase transitions were detected. The first occurs at 1908 °C and disappears in second heating run if the temperature is raised too much. Furthermore, a second one was detected at 2121 °C. The phase relations of NdLuO3 were investigated. A mixture of solid solutions in the cubic C and in the monoclinic B rare earth oxide structure exists between 1200 and 1650 °C. The C‐phase is dominated by Lu content while the B‐phase is Nd rich. With rising temperature, the portion of Nd in the C‐phase is increased and lowered for the B‐phase. No evidence for stability of perovskitic NdLuO3 could be found. Thermal signals up to 2184 °C were examined.