【摘要】：釔鋁石榴石(YAG)屬于立方晶系,具有穩(wěn)定的物理和化學(xué)性質(zhì),這些特性使YAG廣泛應(yīng)用于結(jié)構(gòu)和功能材料等領(lǐng)域。鈰摻雜釔鋁石榴石(Ce:YAG)黃色熒光粉,是目前應(yīng)用最廣泛的熒光粉,可與藍(lán)光芯片可以組合制備白光LED,被廣泛應(yīng)用于照明和背光源等領(lǐng)域。目前市場(chǎng)上的產(chǎn)品均是由有機(jī)樹脂與熒光粉體混合進(jìn)行封裝組合,存在耐熱差、熱導(dǎo)率低、易老化和發(fā)光不均等問題,將Ce:YAG熒光粉體制備成透明陶瓷作為L(zhǎng)ED背光源和封裝材料可以明顯改善上述問題。論文采用沖擊射流反應(yīng)法(CIJR)合成Ce:YAG納米熒光粉體,使用真空高溫?zé)Y(jié)技術(shù)制備Ce:YAG透明陶瓷。系統(tǒng)研究了粉體合成工藝、熔鹽法煅燒粉體、部分稀土元素?fù)诫s對(duì)Ce:YAG熒光粉體性能的影響,探討了添加劑、燒結(jié)溫度、保溫時(shí)間等因素對(duì)制備透明陶瓷的影響,利用SEM、XRD、PL等儀器分析手段對(duì)制備的粉體和陶瓷進(jìn)行了表征。CIJR反應(yīng)器合成的粉體具有優(yōu)秀的分散性和熒光性能,合成工藝條件為:加料速度10m L/min,(NH4)2SO4分散劑2wt%,Ce摻雜量3.0%;前驅(qū)體經(jīng)過(guò)1000℃煅燒5h獲得純YAG相。論文探討了熔鹽(KCl)法煅燒Ce:YAG熒光粉體的影響,最佳煅燒工藝為熔鹽用量R=1:3,在900℃煅燒8h能夠得到晶粒較為規(guī)則且熒光強(qiáng)度較強(qiáng)的粉體,同時(shí)添加10wt%的Ba Cl2能夠有效的減小晶粒的粒。論文研究了三種稀土元素Gd、Tb、Pr摻雜對(duì)Ce:YAG熒光粉體的影響:Gd和Tb均能使Ce:YAG的發(fā)射峰發(fā)生紅移,Pr的摻雜會(huì)在609nm處增加發(fā)射峰,雖然摻雜都能增加紅光成分,但是會(huì)降低熒光粉體的熒光強(qiáng)度,通過(guò)正交實(shí)驗(yàn)優(yōu)化出最佳熒光粉體組成為(Y0.67Gd0.2Tb0.1Ce0.03)3Al5O12。采用三步燒結(jié)工藝制備Ce:YAG透明陶瓷,燒結(jié)助劑TEOS和Mg O,能夠在較低的溫度下產(chǎn)生液相,并且均能有效減少晶粒異常生長(zhǎng),用量過(guò)多將會(huì)引入第二相,最佳添加量為0.8wt%TEOS和0.01wt%Mg O。在真空燒結(jié)爐中將坯體加熱至1280℃和1400℃各保溫2h,接著升溫至1680℃燒結(jié)8h,降溫取出后在空氣氛中1450℃退火2h,最后經(jīng)打磨和拋光得到透明陶瓷,其在800nm處最大的透過(guò)率為16.3%。通過(guò)調(diào)節(jié)陶瓷片的厚度可以調(diào)節(jié)效率、色溫、顯色指數(shù)等,能夠得到白光,由于缺少紅光成分,顯色指數(shù)最高為57.3,離標(biāo)準(zhǔn)白光存在差距。
[Abstract]:Yttrium aluminum garnet (YAG) belongs to cubic system and has stable physical and chemical properties. These properties make YAG widely used in structural and functional materials. Ce doped yttrium aluminum garnet (Ce:YAG) yellow phosphor is the most widely used phosphor. It can be combined with blue chip to prepare white LED. At present, all the products on the market are encapsulated by organic resin and phosphor, which have the problems of poor heat resistance, low thermal conductivity, easy aging and uneven luminescence. Transparent ceramics prepared from Ce:YAG phosphors can be used as backlight source and packaging material for LED. In this paper, Ce:YAG nanocrystalline phosphors were synthesized by impinging jet reaction method (CIJR) and Ce:YAG transparent ceramics were prepared by vacuum high temperature sintering. The effects of powder synthesis, molten salt calcination and rare earth element doping on the properties of Ce:YAG phosphors were systematically studied. The effects of additives, sintering temperature and holding time on the preparation of transparent ceramics were discussed. The powder and ceramics prepared by SEMX XRDPL were characterized by means of SEM, XRDPL and other instruments. The powders synthesized in the reactor of .CIJR had excellent dispersibility and fluorescence properties. The synthetic conditions are as follows: (NH4) 2SO4 dispersant, (10 mL 路min), (NH4) 2SO4 dispersant, 2 wtand ce doping amount 3.0 and the precursor calcined at 1000 鈩，

本文編號(hào)：2157968