【作者】 刘桂霞；

【导师】 孙多先；

【作者基本信息】 天津大学 ， 应用化学， 2004， 博士

【摘要】 由于纳微米颗粒的包覆在材料改性和新功能性质的附加方面的突出特点，从而得到了广泛的研究和应用。本论文以稀土纳微米颗粒的包覆作为研究重点，制备出具有特定功能的核-壳结构的稀土纳微米包覆材料，并对其性能进行了研究，得到了一些有创新性的结果。首次将稀土纳米CeO2和水性聚氨酯复合，得到了包覆有CeO2纳米粒子的水性聚氨酯微乳液，表征结果表明， CeO2和聚氨酯通过静电作用、化学键作用和吸附层媒介作用结合在一起的。包覆后的复合材料对紫外线有很好的吸收作用，该复合材料可望成为一种性能优良的紫外吸收材料。通过与高分子的复合，使CeO2纳米粒子的应用成为可能。首次在纳米SiO2表面包覆一层Gd2O3:Eu稀土复合氧化物, 得到了核-壳结构的复合颗粒，表征结果表明，均匀包覆层的厚度为10-20nm；SiO2核和Gd2O3:Eu壳层物质之间通过化学键Si-O-Gd 键的作用结合在一起；由于包覆层纳米晶的尺寸效应和界面效应使XRD衍射峰和荧光光谱发射峰出现了宽化现象。包覆后使SiO2从无定型向晶型转变的温度明显降低。通过包覆可以节约稀土元素的用量，大大的降低了成本。对于节省我国宝贵的稀土资源具有重要的社会价值。 (Y,Gd)BO3:Eu3+作为PDP用荧光粉的红粉材料存在色纯度差的弱点，为了提高其色纯度，本文首次采用室温固相法在微米级(Y,Gd)BO3:Eu3+颗粒表面包覆一层10nm左右的均匀的氧化铁的包覆层。包覆后 (Y,Gd)BO3:Eu3+红粉的色纯度得到了提高。此法为改善红粉色纯度提供了一种崭新实用的方法。 纳微米级的Gd2O3:Eu荧光粉颗粒，表面存在很多缺陷，并具有大的比表面积，易团聚，从而影响荧光粉的发光性能。本文首次采用室温固相法在Gd2O3:Eu颗粒表面包覆了一层纳米SiO2保护层，增加了其稳定性。SiO2通过化学键Si-O-Gd 连接到Gd2O3:Eu3+颗粒表面的。包覆SiO2后的Gd2O3:Eu3+荧光粉颗粒仍具有很好的发光性能。 通过对以上体系的包覆机理的探讨，得到了初步的表面纳米包覆的模型，对于纳米包覆及界面科学的研究具有一定的参考意义。更多还原

【Abstract】 Coating of nanometer and micrometer particles has been studied widely for their characteristic of material modification and addition of new function. In this dissertation, Some special function and core-shell structure rare earth nanometer and micrometer coating materials have been synthesized, the properties have been studied, and some creative and meaningful results were obtained. It was the first time that the nano-ceria and aqueous polyurethane was combined together, the microemulsion of aqueous polyurethane coating ceria nanoparticles was obtained and characterized. The results showed that the ceria is combined with polyurethane by electrostatic action, chemical bond and absorption media action. The compounds have better absorption for ultraviolet, which can be used as the ultraviolet absorption materials. And, by combining the polymer, the application of ceria nanoparticles becomes possible. It was the first time that the silica nanoparticles was coated with Gd2O3:Eu rare-earth oxides, then the core-shell structure compound particles were obtained. The characterizations showed that the thickness of uniform coating is in 10-20nm; the silica core is linked with the Gd2O3:Eu shell by chemical bond Si-O-Gd; because of the size effects and interface effects of nano-crystal coating, the diffraction and emission peaks become broadened. And at the same time, the transfer temperature of silica from amorphous to crystal is decreased. After coating on the surface of silica, Gd2O3:Eu has better luminescence properties. Which can reduce the cost and save the rare-earth materials. It is important to save our precious rare-earth resource. (Y,Gd)BO3:Eu3+ was the red phosphors for PDP, which had poor color purity. In this dissertation, Solid state reaction method at room temperature was firstly used for coating the (Y,Gd)BO3:Eu3+ particles with hematite. The thickness of uniform hematite coating is about 10nm. And the color purity is increased by coating thin hematite. This method provides a new and practical method to improve the color purity of red phosphors. Nanometer and micrometer sized Gd2O3:Eu have many defects in the surface, and have high specific surface area, which can make the particles agglomerate, so the phosphors’ lightness would be decreased. In this dissertation, Solid state reaction method at room temperature was firstly used to coat Gd2O3:Eu3+ particles with nano-silica coatings. The silica coatings are linked with Gd2O3:Eu by chemical bond Si-O-Gd; and the Gd2O3:Eu still has better luminescence properties after coating silica. By discussing the coating mechanics of these systems, we obtain some coating model, which will have some reference value to study nano-coating and interface science.更多还原