[Preparation and optical properties of MgAl2O4/Ce:YAG transparent ceramics].

ABSTRACT

High-purity ultrafine MgAl2O4 powder was synthesized by metal-alkoxide method and calcining for 2-4 h. And then MgAl2O4/CeYAG transparent ceramics were fabricated by hot-pressed sintering and hot isostatic pressed sintering technique with YAGCe powder and MgAl2O4 powder. The transparent ceramics were characterized by XRD, SEM, EDS and fluorescence spectrometer, respectively. The results show that the crystal phase of the transparent ceramic was composed of MgAl2O4 and YAG,and the YAG phase dispersed well in the matrix of MgAl2O4. The excitation spectra had a weak band at 345 nm and a strong band at 475 nm. The broad emission peaks at about 533 nm were attributed to 5d-->4f transition of Ce3+ ions. Decay curves for the fluorescence of MgAl2O4/CeYAG transparent ceramic test show that the lifetime of the CeYAG glass ceramic was 59.74 ns. All results show that MgAl2O4/CeYAG transparent ceramic may be a promising fluorescent material for white LED applications.