Spray pyrolysis using FEAG (Filter Expansion Aerosol Generator) process was applied to the preparation of multicomponent phosphor materials ; red emitting YAG:Eu, $Y_2O_3$:Eu and Ultrasonic process was applied to the preparation of multi-layer phosphor material ; YAG coated $Y_2O_3$:Eu. The morphology and crystalline phase of the prepared particles were investigated by SEM (Scanning Electron Microscopy), XRD (X-Ray Diffraction) and CPSA (Centrifugal Particle Size Analyser). Optimum conditions for the preparation and post-treatment of particles with good luminescence were determined by CL (cathodoluminescence) and PL (photoluminescence). The stability for the electrical beam and the luminescence characteristics of YAG coated $Y_2O_3$:Eu were investigated by long time irradiation.
Spherical and non-agglomerated particles with submicron size were prepared by spray pyrolysis. The mean size of the particles increased with the solution concentration. Phase-pure particles were prepared at lower temperatures than solid state reactions. The particles with pure phase and high crystallinity had high brightness. The optimum post-treatment conditions of the YAG:Eu and $Y_2O_3$:Eu particles were 1400℃ for 5 hrs and 1500℃ for 1 hr, respectively. The luminescence characteristics of YAG coated $Y_2O_3$:Eu particles showed the characteristics of YAG:Eu and $Y_2O_3$:Eu. The CL intensity of YAG:Eu coated $Y_2O_3$:Eu saturated to the intensity of YAG:Eu as the YAG coating thickness was increased. The stability for the electrical beam was sharply improved after coating.