Kinetic effects of substitution Er3+ for Y3+ in (Y1-xErx)3Al5O12 garnet

The crystallization kinetics of erbium-substituted yttrium aluminum garnet (Er:YAG) from the amorphous phase was studied depending on the degree of substitution of yttrium by erbium: (Y_1-xEr_x)₃Al₅O₁₂, x = 0 – 0.9. The corresponding series of nanopowders were synthesized using the sol-gel method with binary sols as the starting materials. Crystallized single-phase Er:YAG powders were obtained at temperatures as low as 1370 K through the formation of intermediate phases. The crystallization kinetics of the Er:YAG precursors was analyzed using non-isothermal differential scanning calorimetry and X-ray diffraction analysis. The proposed unified crystallization model, based on which the kinetic parameters of the crystallization process of the Er:YAG from the amorphous phase were determined, depending on the content of erbium oxide. Time-temperature-transformation curves were developed from the obtained data to determine the optimal modes in the heat treatment and sintering of optical ceramics. Er:YAG transparent ceramics were obtained by vacuum sintering of sol-gel powders.