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荧光粉(YAG：Tb)的工艺。实验考察了反应条件(反应温度、反应压力、反应时间、溶液组成和溶液的碱摩尔比)与产物性质(晶体结构、粒度和粒度分布)的关系。以Al(NO_3)_3、Y(NO_3)_3和TbCl_3混合水溶液为原料，制备了Al(NO_3)_3、Y(NO_3)_3和TbCl3混合溶液。用钾水溶液改变溶液的碱摩尔比。实验是在新研制的流体式装置上进行的。由此可见，碱摩尔比是影响单相YAG颗粒生成的重要因素。反应温度和压力影响颗粒的晶粒度和晶格常数。高温和低压导致生成结晶度较高的颗粒。通过与传统固相反应法制备的颗粒物的比较，研究了颗粒物的发射特性。用该方法制得的颗粒性能与常规方法相当。连续(1.5g/h)和快速(&lt；1秒)用超临界水结晶法制备荧光粉(YAG：Tb)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.