Production of Phosphor (YAG : Tb) particles by Supercritical Water Crystallization Method

本研究的目的是开发一种快速连续的超临界水结晶法制备YAG: Tb荧光粉细颗粒的工艺。实验研究了所制颗粒的性质（晶体结构、粒度和粒度分布）与反应条件（反应温度、压力、反应时间、溶液组成和溶液碱摩尔比）之间的关系。以Al (NO_3) _3、Y (NO_3) _3和TbCl_3混合水溶液为起始原料。用钾溶液改变溶液的碱摩尔比。实验是用一种新研制的流型装置进行的。结果表明，碱摩尔比是制备单相YAG颗粒的重要因素。反应温度和反应压力影响颗粒的晶粒尺寸和晶格常数。高温和低压导致生产出高结晶度的颗粒。通过与传统固相反应法制备颗粒的比较，研究了所制备颗粒的发射特性。该方法制备的颗粒性能与传统方法相当。用超临界水结晶法连续（1.5g/h）和快速（<1秒）生产荧光粉（YAG: Tb）细颗粒是可行的。

The objective of this research was to develop a repid and continuous production process for phosphor (YAG : Tb) fine particles by supercritical water crystallization method. The relationship between properties (crystal sturacture, particle size and particle size distribution) of particles produced and reaction conditions (reaction temperature, pressure, reaction time, composition of solution and alkali mole ration of solution) was investigated experimentally. Al (NO_3) _3, Y (NO_3) _3 and TbCl_3 mixed aqueous solution was used as the starting materials. Potassium aqueous solution was used to vary the alkali mole retio of solution. Experiments were performed with a newly-deveolped flow type apparatus. From these results, the alkali mole ratio was important factor for production of single phase YAG particles. Reaction temperature and pressure affected crystalline size and lattice constant of particles. High temperature and low pressure leaded to produce particles with high crystallinity. Emission properties of particles produced was studied by comparison with particles produced by a conventional solid state reaction method. Properties of particles produced by the method in this work were comparable with the conventional method. Continuous (1.5g/h) and rapid (<1 sec.) production of phosphor (YAG : Tb) fine particles was found to be practical with the supercritical water crystallization method.