Garnet Phase Formation in Y2O3–Lu2O3–Yb2O3–Er2O3–Al2O3 System During the Synthesis of Nanocrystalline Weakly Agglomerated Ceramic Powders by Coprecipitation Method Using Ammonium Sulfate

For the first time, we obtained a series of ceramic powders with garnet structure, (Y_1–xLu_x)₃Yb_0.15Er_0.03Al₅O₁₂ (YLuAG), using the coprecipitation method with ammonium sulfate. The atomic ratio of Y³⁺/Lu³⁺ cations was varied from 80/20 to 20/80. It was determined that the formation of the garnet phase under the synthesis conditions proceeds through the formation of intermediate phases, whose composition depends on the Y/Lu ratio in the initial salt solution. The differential thermal analysis (DTA) of precursor powders and x-ray diffraction (XRD) of (Y_1–xLu_x)₃Yb_0.15Er_0.03Al₅O₁₂ ceramic powders obtained at 800, 900, 1000, and 1150°C facilitated the identification of the temperature ranges for the formation and decomposition of intermediate crystalline phases obtained during the thermal synthesis of the garnet phase, including Y₂O₂SO₄, Y₂(SO₄)₃, Lu₂(SO₄)₃, and Lu_1–xY_xAlO₃.