Co-Precipitation Synthesis of Gadolinium Aluminum Gallium Oxide (GAGG) via Different Precipitants

In order to obtain a uniform transparent ceramic scintillator, well-dispersed fine starting powders with high-purity, small grain size, spherical morphology and high sinter-ability are necessary. In this study, Ce³⁺ doped gadolinium aluminum gallium garnet Gd₃Al₃Ga₂O₁₂ (GAGG) powders were synthesized by the co-precipitation method. NH₄OH, NH₄HCO₃ and the mixed solution of NH₄OH and NH₄HCO₃ were used as precipitants, respectively. The precursor composition, phase formation process, microstructure, morphology, particle size distribution and luminescent properties of obtained GAGG powders were measured. The results show that powders prepared using the mixed precipitant exhibit the best microstructural morphology, good sinter-ability and highest luminescent intensity. Pure GAGG polycrystalline powders could be obtained at about 950°C for 1.5 h and the average size of the particles is about 50 nm. The photoluminescence spectrum shows a strong green-yellow emission near 540 nm.