氧化铝模板法制备细粒径高结晶YAG颗粒的研究
发布时间：2018-10-09 18:36
【摘要】：白光LED是目前新兴的绿色光源之一,具有节能、环保、寿命长、体积小、响应速度快等优势,应用前景广阔。YAG荧光粉性能对白光LED的光色性能有着至关重要的影响。目前商用的YAG荧光粉使用传统的高温固相法制备,颗粒尺寸过大且粒径分布范围不均匀。制备高结晶性细粒径YAG荧光粉是本领域的研究难点,也具有良好的应用前景。本文首先研制出微米级α-Al2O3分散粉体和纳米Y2O3粉体,并以其为原料研究熔盐法制备高结晶性分散YAG粉体的技术,通过控制反应过程,成功制备出小粒径的YAG颗粒。本文采用化学沉淀法制备出微米级α-Al2O3粉体,研究了搅拌速度、促进剂、分散剂、热处理工艺等参数对α-Al2O3颗粒粒径及形貌的影响。研究表明：搅拌速度提高可以减小α-Al2O3颗粒的粒径；加入促进剂NH4F能够控制α-Al2O3趋于片状生长；提高煅烧温度有利于得到小粒径的α-Al2O3颗粒；采用随炉加热的方式并适当提高保温时间可以得到形貌规则的颗粒。在此基础上制备出粒径在3μm左右、分散性良好的片状α-Al2O3粉体。本文分别使用尿素沉淀法和碳酸氢铵沉淀法制备出纳米Y2O3粉体,研究发现：尿素沉淀法制备的颗粒粒径过大；碳酸氢铵沉淀法制备出小粒径的Y2O3颗粒；煅烧温度越低,越有利于颗粒的分散性。本文最终制备出100nm左右的Y2O3颗粒。本文以自制的α-Al2O3和纳米Y2O3粉体为原料,采用熔盐法制备出粒径小于5μm的YAG粉体。研究了不同熔盐体系、焙烧温度等因素对YAG产物的影响,并对制备工艺进行了改进,研究了三次处理对制备YAG颗粒的影响。研究发现,在NaCl熔盐中,当反应温度较低时,纳米Y2O3颗粒包裹在α-Al2O3颗粒表面；将此包裹体在KCl熔盐中1200℃焙烧,包裹更为致密；再在K2SO4熔盐中1400℃焙烧处理,成功得到小粒径的YAG颗粒,颗粒大小与α-Al2O3模板存在依赖性。本文分析了α-Al2O3模板法制备小粒径YAG颗粒的机理。本文认为,熔盐促进了纳米Y2O3颗粒运动到α-Al2O3颗粒表面；在接触点生成Y4Al2O9相；随着温度的升高,在α-Al2O3和Y2O3颗粒的界面进一步生成中间相YAlO3。最终转化为YAG单相。
[Abstract]:White LED is one of the new green light sources. It has the advantages of energy saving, environmental protection, long life, small size and fast response. At present, commercial YAG phosphors are prepared by traditional high temperature solid state method. The particle size is too large and the particle size distribution is uneven. The preparation of YAG phosphors with high crystallinity and fine particle size is a difficult point in this field and has a good prospect of application. In this paper, micrometer 伪 -Al 2O 3 dispersion powder and nanometer Y2O3 powder were prepared, and the technology of preparing high crystalline dispersed YAG powder by molten salt method was studied. Small diameter YAG particles were successfully prepared by controlling the reaction process. In this paper, micrometer 伪 -Al _ 2O _ 3 powders were prepared by chemical precipitation method. The effects of stirring speed, accelerator, dispersant and heat treatment process on the size and morphology of 伪 -Al _ 2O _ 3 particles were studied. The results show that the particle size of 伪 -Al _ 2O _ 3 particles can be reduced with the increase of stirring speed, the growth of 伪 -Al _ 2O _ 3 particles can be controlled by adding accelerator NH4F, and the small size 伪 -Al _ 2O _ 3 particles can be obtained by increasing the calcination temperature. The particles with regular morphology can be obtained by heating with furnace and properly increasing the holding time. On this basis, the flake 伪 -Al _ 2O _ 3 powders with a particle size of about 3 渭 m and good dispersion were prepared. In this paper, nanometer Y2O3 powders were prepared by urea precipitation method and ammonium bicarbonate precipitation method respectively. It was found that the particle size of urea precipitation method was too large, the small diameter of Y2O3 particles was prepared by ammonium bicarbonate precipitation method, and the calcining temperature was lower. The better the dispersity of the particles is. In this paper, Y2O3 particles about 100nm were prepared. In this paper, 伪 -Al _ 2O _ 3 and nano-sized Y2O3 powders were used as raw materials to prepare YAG powders with diameter less than 5 渭 m by molten salt method. The effects of different molten salt system, calcination temperature and other factors on the YAG products were studied, and the preparation process was improved. The effect of three treatments on the preparation of YAG particles was studied. It is found that when the reaction temperature is low, the nanocrystalline Y2O3 particles are encapsulated on the surface of 伪 -Al _ 2O _ 3 particles in the NaCl molten salt, the inclusion is calcined at 1200 鈩，
本文编号：2260364
[Abstract]:White LED is one of the new green light sources. It has the advantages of energy saving, environmental protection, long life, small size and fast response. At present, commercial YAG phosphors are prepared by traditional high temperature solid state method. The particle size is too large and the particle size distribution is uneven. The preparation of YAG phosphors with high crystallinity and fine particle size is a difficult point in this field and has a good prospect of application. In this paper, micrometer 伪 -Al 2O 3 dispersion powder and nanometer Y2O3 powder were prepared, and the technology of preparing high crystalline dispersed YAG powder by molten salt method was studied. Small diameter YAG particles were successfully prepared by controlling the reaction process. In this paper, micrometer 伪 -Al _ 2O _ 3 powders were prepared by chemical precipitation method. The effects of stirring speed, accelerator, dispersant and heat treatment process on the size and morphology of 伪 -Al _ 2O _ 3 particles were studied. The results show that the particle size of 伪 -Al _ 2O _ 3 particles can be reduced with the increase of stirring speed, the growth of 伪 -Al _ 2O _ 3 particles can be controlled by adding accelerator NH4F, and the small size 伪 -Al _ 2O _ 3 particles can be obtained by increasing the calcination temperature. The particles with regular morphology can be obtained by heating with furnace and properly increasing the holding time. On this basis, the flake 伪 -Al _ 2O _ 3 powders with a particle size of about 3 渭 m and good dispersion were prepared. In this paper, nanometer Y2O3 powders were prepared by urea precipitation method and ammonium bicarbonate precipitation method respectively. It was found that the particle size of urea precipitation method was too large, the small diameter of Y2O3 particles was prepared by ammonium bicarbonate precipitation method, and the calcining temperature was lower. The better the dispersity of the particles is. In this paper, Y2O3 particles about 100nm were prepared. In this paper, 伪 -Al _ 2O _ 3 and nano-sized Y2O3 powders were used as raw materials to prepare YAG powders with diameter less than 5 渭 m by molten salt method. The effects of different molten salt system, calcination temperature and other factors on the YAG products were studied, and the preparation process was improved. The effect of three treatments on the preparation of YAG particles was studied. It is found that when the reaction temperature is low, the nanocrystalline Y2O3 particles are encapsulated on the surface of 伪 -Al _ 2O _ 3 particles in the NaCl molten salt, the inclusion is calcined at 1200 鈩，
本文编号：2260364
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