铌酸盐粉体的熔盐法制备及其发光性能的研究
发布时间：2018-08-05 13:03
【摘要】：发光材料在现代生活当中扮演着至关重要的角色,稀土发光材料作为发光材料中的重要一部分被广泛的应用于荧光探测分析、灯光照明系统和医用影像检测等各个领域。其中的铌酸盐功能材料不仅拥有优良的化学和热稳定性,同时还在压电和非线性光学方面具有良好的性质,成为一种很重要的发光基质材料。目前,通常用来合成铌酸盐粉体的方法主要是高温固相反应法,这种方法的优点就是过程比较简单,适合于大规模的生产,但反应过程能量需求大,反应所需时间比较长,而且产物离子分布不均匀,容易混入杂质。熔盐合成技术以其合成温度低、产物形貌可控、设备简单等优势近年来在材料合成领域得到广泛应用。本论文采用熔盐法合成K2LaNb5O15粉体,系统的通过改变熔盐用量,煅烧温度,保温时间以及不同熔盐体系等条件来研究K2LaNb5O15粉体的晶体结构和形貌,分析了熔盐法合成K2LaNb5O15粉体的反应机理,最终确定了最佳的制备工艺流程;研究了K2LaNb5O15粉体及掺杂不同稀土离子的K2LaNb5O15:Ln3+(Ln3+=Eu3+,Tb3+)荧光粉的发光特性及发光机理,主要研究内容如下:1、以氧化镧、氧化铌、氯化钾和硫酸钾为原料,采用熔盐法制备了K2LaNb5O15粉体,探讨了熔盐用量、煅烧温度、保温时间以及不同熔盐体系等对K2LaNb5O15粉体的晶体结构和微观形貌的影响。研究结果表明,合成K2LaNb5O15粉体的最佳熔盐配比是KCl实际/KCl理论=7.5:1此时产物为钨青铜结构,形貌比较均匀,呈长10um、直径1um的棒状结构;KCl在770℃时融化,K2LaNb5O15开始结晶,随着温度的升高,K2LaNb5O15粉体的结晶度相应提高,K2LaNb5O15粉体的最佳焙烧温度是1000℃,此时结晶完全,粉体形貌为均匀的棒状;保温时间为2h和3h时,合成的样品形貌均匀性最好,为长度集中在10um、直径1um的棒状结构。采用KCl做单一熔盐时,制备的样品的微观形貌基本都是较细长的棒状,形貌比较均匀和规整。随着熔盐中K2SO4的增加,样品的形貌均匀性变差,短柱状颗粒增多。2、通过在K2LaNb5O15基质中掺杂不同稀土离子Ln3+(Eu3+,Tb3+),合成了具有层状钨青铜结构的K2LaNb5O15:Ln3+荧光粉,并且使用用荧光光谱仪测定了基质K2LaNb5O15粉体和K2LaNb5O15:Ln3+粉体的激发和发射光谱,并分析了其发光机理。结果表明,K2LaNb5O15粉体自身具有很强的蓝光发射,属于自激活基质发光。K2LaNb5O15:Ln3+荧光粉的激发-发射光谱是由基质的谱带和稀土离子自身f-f特征跃迁谱线两部分所构成,说明K2LaNb5O15和稀土离子之间存在着能量传递关系。
[Abstract]:Luminescent materials play an important role in modern life. As an important part of luminescent materials, rare earth luminescent materials are widely used in various fields, such as fluorescence detection and analysis, lighting systems and medical image detection. The niobate functional materials not only have excellent chemical and thermal stability, but also have good properties in piezoelectric and nonlinear optics. At present, the main method used to synthesize niobate powder is the high temperature solid state reaction method. The advantage of this method is that the process is relatively simple and suitable for large-scale production, but the reaction process requires a large amount of energy and takes a long time to react. Moreover, the ion distribution of the product is not uniform, and it is easy to be mixed with impurities. Molten salt synthesis technology has been widely used in the field of material synthesis in recent years because of its low synthesis temperature, controllable product morphology, simple equipment and so on. In this paper, K2LaNb5O15 powder was synthesized by molten salt method. The crystal structure and morphology of K2LaNb5O15 powder were studied by changing the amount of molten salt, calcining temperature, holding time and different molten salt system. The reaction mechanism of K2LaNb5O15 powder synthesized by molten salt method was analyzed, and the optimum preparation process was determined, and the luminescence characteristics and mechanism of K2LaNb5O15 powder and K2LaNb5O15:Ln3 (Ln3 EU 3 EU 3 Tb 3) phosphor doped with different rare earth ions were studied. The main research contents are as follows: K2LaNb5O15 powder was prepared by molten salt method with lanthanum oxide, niobium oxide, potassium chloride and potassium sulfate as raw materials. The amount of molten salt and calcination temperature were discussed. The effects of holding time and different molten salt systems on the crystal structure and microstructure of K2LaNb5O15 powders were investigated. The results show that the optimum ratio of molten salt to synthesized K2LaNb5O15 powder is that the product of KCl's actual / KCl theory of 7.5: 1 is tungsten bronze with a uniform morphology and a long length of 10 um.The rod-like structure of 1um melts KCl at 770 鈩，
本文编号：2165880
[Abstract]:Luminescent materials play an important role in modern life. As an important part of luminescent materials, rare earth luminescent materials are widely used in various fields, such as fluorescence detection and analysis, lighting systems and medical image detection. The niobate functional materials not only have excellent chemical and thermal stability, but also have good properties in piezoelectric and nonlinear optics. At present, the main method used to synthesize niobate powder is the high temperature solid state reaction method. The advantage of this method is that the process is relatively simple and suitable for large-scale production, but the reaction process requires a large amount of energy and takes a long time to react. Moreover, the ion distribution of the product is not uniform, and it is easy to be mixed with impurities. Molten salt synthesis technology has been widely used in the field of material synthesis in recent years because of its low synthesis temperature, controllable product morphology, simple equipment and so on. In this paper, K2LaNb5O15 powder was synthesized by molten salt method. The crystal structure and morphology of K2LaNb5O15 powder were studied by changing the amount of molten salt, calcining temperature, holding time and different molten salt system. The reaction mechanism of K2LaNb5O15 powder synthesized by molten salt method was analyzed, and the optimum preparation process was determined, and the luminescence characteristics and mechanism of K2LaNb5O15 powder and K2LaNb5O15:Ln3 (Ln3 EU 3 EU 3 Tb 3) phosphor doped with different rare earth ions were studied. The main research contents are as follows: K2LaNb5O15 powder was prepared by molten salt method with lanthanum oxide, niobium oxide, potassium chloride and potassium sulfate as raw materials. The amount of molten salt and calcination temperature were discussed. The effects of holding time and different molten salt systems on the crystal structure and microstructure of K2LaNb5O15 powders were investigated. The results show that the optimum ratio of molten salt to synthesized K2LaNb5O15 powder is that the product of KCl's actual / KCl theory of 7.5: 1 is tungsten bronze with a uniform morphology and a long length of 10 um.The rod-like structure of 1um melts KCl at 770 鈩，
本文编号：2165880
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