稀土离子论文：稀土发光材料CaWO_4：Eu(3+)的制备及其性能表征

稀土离子论文：稀土发光材料CaWO_4：Eu（3+）的制备及其性能表征
【中文摘要】稀土离子特殊的4f电子组态能级和电荷转移带结构决定了稀土离子掺杂的发光材料具有许多优异性能,如发光强度高、余辉时间长、发射光波长可调、无辐射、无污染等。

基于人们对红色纳米稀土发光材料的实用价值越来越多的关注,以及相关领域内对该材料的制备技术的研究还不够成熟的现状,我们将主要研究方向定位在以降低合成温度、简化工艺流程、缩短反应时间、制备出纯相且颗粒形态可控的产物为,寻找高效实用且能耗低的制备技术。

影响发光材料性能的主要因素是材料的平均粒径、Eu3+的掺杂量以及材料的结晶程度等。

化学沉淀法的优势在于能制备出颗粒粒径大小可控且分散均匀的产品,而高能球磨法能使粉体产生塑性变形及相变,大大
提高了能量利用率,扩展了激活剂在基质中的固溶度。

因此,本课题充分利用两种方法的优势,在前人工作的基础上成功地合成了粒度适当,且发光性能优越的CaWO4:Eu3+发光材料。

本文研究了通过改变沉淀pH值、沉淀温度、Eu3+的掺杂量以及煅烧温度等参数采用化学沉淀法制备出不同的CaWO4:Eu3+发光材料,利用XRD、SEM和FL等手段对材料的性能进行表征；研究了通过改变球料比、球磨温度、球磨时间以及Eu3+的掺杂量等球磨参数采用高能球磨法制备出不同的
CaWO4:Eu3+粉体,利用XRD、SEM和FL等手段表征所得粉体。

最终确定发光性能最好的材料制备工艺条件。

实验结果表明：1.将在沉淀
pH值为7,沉淀温度为40。

C条件下制得的前驱体在马弗炉中于950℃下煅烧,Eu3+掺杂量为20 mo1%的CaWO4:Eu3+粉体平均粒径适当且均匀,发光强度最高。

2.当球料比为12：1时,将前驱体在600℃下球磨1 h,Eu3+掺杂量为30 mo1%的CaWO4:Eu3+粉体平均粒径小而均匀,发光强度最高。

3.相比化学沉淀法,高能球磨法能使CaWO4:Eu3+发光材料的合成温度从950。

C降低至600℃,保温时间从2h缩短到1h,Eu3+掺杂量从20mol%提高到30mol%,同时有效地提高了发光强度和热稳
定性,得到无团聚、分散均匀的发光材料颗粒。

【英文摘要】Luminescent materials doped with rare-earth ions have much excellent performance because of its’special electron configuration energy level of 4f and structure of charge transition zones, and the luminescent materials have the advantages of high luminous intensity, long after time, controllable emission wavelength, no radiation, no pollution, etc. Based on the situations of more and more attention to practical value of nanometer red rare-earth luminescent materials and immature researches on preparation technologies of the materials, we concentrated main efforts on lowing synthesis temperature, simplifying process flow, shortening reaction time and preparing products with pure phase and controllable particle form. In addition, we also concentrated efforts on finding a high-efficient, practical and low energy
consumption preparation technology. The performance of luminescent materials is mainly determined by mean particle size, doping amount of Eu3+, crystallization degree etc. On one hand, a method of chemical precipitation has advantage of capability of preparing products with size-controllable and uniformly dispersed particles; on the other hand, high-energy ball milling method can lead power to carry out plastic deformation and phase transition, energy utilization rate is improved greatly, and solid solubility of activator in substrate is extended. Therefore, this subject fully utilized the advantages of the two methods and successfully synthesized luminescent material CaWO4:Eu3+ with proper particle size and superior luminescent properties.This article studied on preparing a series of luminescent material CaWO4:Eu3+ by the method of chemical precipitation through changing some factors, such as precipitation pH value, precipitation temperature, doping amount of Eu3+, calcining temperature, etc., and then, the prepared materials are characterized by some measures, such as XRD、SEM and FL. At the same time, the article studied on preparing a series of luminescent material CaWO4:Eu3+ by the method of high energy ball milling through changing some factors, such as ratio of milling media to material, ball
milling temperature, ball milling time, doping amount of Eu3+ etc., and then, the prepared materials are characterized by some measures, such as XRD, SEM and FL. For this, we aim at obtaining the optimal preparing technology factors of the luminescent material CaWO4:Eu3+ with the strongest luminescent intensity.It is demonstrated by the experiments that:firstly, the strongest luminescent CaWO4:20% Eu3+ powder with proper and uniform particle size is prepared in a muffle at 950℃of calcining temperature for 2 hours from a precursor which is prepared at 7 of precipitation pH value and 40℃of precipitation temperature; secondly, the strongest luminescent CaWO4:30%Eu3+powder with proper and uniform particle size is prepared by a high energy ball milling method at 600℃for 1h from the precursor which is prepared at 7 of precipitation pH value and 40℃of precipitation temperature, and the ratio of milling media to material is 12:1; thirdly, compared with the chemical precipitation method, the high energy ball milling method can be used for lowing the synthesis temperature from 950℃to 600℃, lowing the reaction time from 2 h to 1 h, and rising the doping amount of Eu3+ from 20% to 30%. At the same time, the luminescent intensity and thermal stability are effectively improved, and uniformly dispersed
luminescent powder particles without glomeration are obtained.
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【关键词】稀土离子发光材料 CaWO4:Eu3+ 高能球磨
【英文关键词】rare-earth ions luminescent materials CaWO4:Eu3+ high energy ball milling。