Synthesis Of Y₂O₃ Microspheres With Controlled-Size By Homogeneous Precipitation Method And Its Properties

Spherical Y₂O₃ powder is mainly used in the preparation of transparent ceramics,luminescent materials and surface coating.The properties of spherical Y₂O₃ powders with different particle sizes are very different,especially the microspherical powder.In this paper,Y₂O₃ microspheres and Y₂O₃ codoped gadolinium-europium-bismuthn multicomponent spherical phosphors are prepared by urea homogeneous precipitation method,and the related properties are tested.In this study,the preparation of microspheres and the characterization of the powders are studied,including FTIR,TG,DTA,the relative density of the sintered body,powder phase analysis and luminescence properties.The process of preparation of Y₂O₃ microspheres by homogeneous precipitation method is as follow:obtain the dried core powder by homogeneous precipitation in the mixed solution of precipitating agent（0.5 mol/L）and metal ion（0.015 mol/L）,whose composition is Y（OH）CO3·0.95H2O and particle size is 354 nm by the analysises of TG-DTA,FT-IR,SEM and laser particle size.Then,according to ideal growth model,coat uniformly in the mixed system of 0.1 g coated core powder,11.71 mL Y（NO3）3 solution and 26.5115 g of urea.Finally,the particle size is about 1200 nm.The Y₂O₃:5at.%Eu3+ spherical phosphor with particle size 1110 nm was also prepared by the similar method.The sintering properties of Y₂O₃ spherical powder with different particle size are systematically studied.The results show that with the increase of particle size,the Shrinkage rate of sintered at the same heating rate slows down and the compactness of the sintered body decreases and the porosity increases and becomes coarse.When heating rate is 10℃/min,the grain size of the sintered body is about 380 nm and the sintering activation energy is 160 kJ/mol for 180 nm powders,which belongs to the grain boundary diffusion at the initial sintering stage.The doping ratio of different elements is changed,and the quaternary phosphors of yttrium,gadolinium,europium and bismuth are synthesized.The change of the intensity of the emitted light under different excitation wavelengths is investigated,and the quaternary system luminescence The performance of Eu3+was compared with that of binary Y₂O₃:5at.%Eu3+.