Phase Equilibria in Quasi-Ternary System Li₂O–Mn₂O₃–Eu₂O₃

Using X-ray powder diffraction and thermal analysis (TG–DSC), samples of the quasi-ternary system Li₂O–Mn₂O₃–Eu₂O₃, synthesized from precursors subjected to preliminary mechanochemical activation and annealed in air at 700–1100°C, have been studied. An assessment is given of the possibility of Mn for Eu substitution in the spinel LiMn_{2 – x}Eu_xO₄. A subsolidus isobaric diagram of the Li₂O–Mn₂O₃–Eu₂O₃ system was constructed. Using models of polythermal sections LiEuO₂–LiMnO₂ and LiEuO₂–LiMn₂O₄, a projection of the liquidus surface of the quasi-ternary system Li₂O–Mn₂O₃–Eu₂O₃ was obtained. The temperatures of eutectic and peritectic equilibria involving three crystalline phases and a melt have been determined.