共查询到19条相似文献,搜索用时 156 毫秒
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采用传统的固相反应法,在1400–1500 ℃下烧结,制备得到Al2O3-Y2O3-ZrO2三相复合陶瓷.样品的结构、形貌和电性能分别用X射线衍射(XRD)、扫描电子显微镜(SEM)及介电谱表征.XRD表明此三相复合体系无其他杂相,加入Y2O3及ZrO2后使得Al2O3成瓷温度降低;SEM表明此体系晶粒直径为200–500 nm,并且样品随烧结温度的升高而变得更加致密,晶界更加清晰;介电损耗谱中出现峰值弛豫现象,根据Cole-Cole复阻抗谱得出其为非德拜弛豫.
关键词:
2O3-Y2O3-ZrO2三相陶瓷')" href="#">Al2O3-Y2O3-ZrO2三相陶瓷
介电弛豫
阻抗谱
热导率 相似文献
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室温下采用射频磁控溅射法,在硅衬底上制备了Y2O3-TiO2氧化物复合薄膜.利用XRD(X-ray diffraction)和AFM( atomic force microscopy)分析观察了退火前后样品的物相、形貌等变化,讨论了致密薄膜的生长机理.实验发现,溅射功率越大,薄膜的平整度和致密度越好.对热处理前后样品的结晶结构和表面形貌的分析结果显示,在本实验参数范围内,随着溅射功率的增大,更多的Y2O3
关键词:
2O3-TiO2薄膜')" href="#">Y2O3-TiO2薄膜
表面形貌
原子力显微镜
磁控溅射 相似文献
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本文通过在前驱液中添加过量钇盐和铈的有机盐,采用三氟乙酸盐-金属有机沉积法(TFA-MOD) 在铝酸镧单晶基体上制备了含有纳米氧化钇和纳米铈酸钡的YBCO薄膜. 与纯YBCO薄膜相比,掺杂Y2O3/BaCeO3的YBCO膜的临界转变温度几乎保持不变,为91 K左右. 而掺杂Y2O3/BaCeO3的YBCO膜的临界电流密度达到5.0 MA/cm2 (77 K, 0T), 是纯YBCO膜临界电流密度的1.5倍.薄膜中的Y2O3和BaCeO3可能在YBCO内部起到了 有效的钉扎磁通作用.
关键词:
钇钡铜氧薄膜
2O3和纳米BaCeO3')" href="#">纳米Y2O3和纳米BaCeO3
磁通钉扎
三氟乙酸盐-金属有机沉积 相似文献
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介绍了一种基于纳米粉末真空烧结技术的新型固体激光材料——Yb:Y2O3多晶陶瓷的制备工艺、物理化学特性、能级结构和光谱特性,并与Yb:YAG单晶进行了对比.采用紧凑型有源镜激光器(CAMIL)的抽运方式,验证了Yb:Y2O3透明陶瓷的激光输出性能.在35W的最大抽运功率下,得到波长1078 nm,功率10.5 W 的连续激光输出,斜率效率达到37.5%.实验中还观察到激光输出波长随抽运功率增加而红移以及随输出耦合镜变化而漂移的现象.Yb:Y2O3多晶陶瓷是一种理想的激光材料,不仅具有与Yb:YAG单晶同样优秀的物理化学性能和光谱特性,而且其热导率和发射带宽约为Yb:YAG单晶的两倍,非常适合于高亮度激光器和超短脉冲激光器领域的发展应用.
关键词:
2O3陶瓷')" href="#">Yb:Y2O3陶瓷
陶瓷激光器
透明陶瓷 相似文献
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采用溶胶-凝胶法合成了Y3Mg2AlSi2O12∶Ce3+荧光粉。用X射线粉晶衍射(XRD)仪对其进行了物相分析,用电子扫描电镜(SEM)观察了该荧光粉的形貌,同时测定了激发光谱及发射光谱。结果表明,Y3Mg2AlSi2O12∶Ce3+的晶体结构与Y3Al5O12(钇铝石榴石)一致,形貌也表现出等轴粒状的特点。发射谱为峰值位于580 nm处的宽带发射,是Ce3+的 4f65d1-4f7特征跃迁发射。激发谱表现为340 nm和468 nm的双峰带,可以被蓝光有效的激发。Ce3+的浓度对发光强度有明显的影响,当Ce3+的摩尔分数为0.06时,发光强度最大。最后考察了成分取代而导致的Y3Mg2AlSi2O12∶Ce3+的物相转变和对发光性能的影响。 相似文献
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研究了La2O3对Yb:Y2O3透明陶瓷光谱性能的影响,添加适量La2O3以后,Yb:Y2O3透明陶瓷的吸收峰和发射峰的位置不变,但由于La3+的离子半径大于Y3+的离子半径,在Y2O3中引入La3+离子后,导致Y2O3晶格常数变大,晶场强度变弱,同时降低了Y2O3晶体的有序度,致使发射峰强度有所下降,发射截面变小.过量的La2O3(x=0.16)造成Yb3+激活离子发射强度明显下降;其荧光寿命在添加La2O3后总体增大45%—60%.
关键词:
氧化镧
氧化钇
透明陶瓷
光谱性能 相似文献
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用共沉淀法制备了Y2O2S:Eu3+,Mg2+,Ti4+红色长余辉材料。测量了材料的电子显微形貌、晶体结构和发射光谱。通过与固相法制备的Y2O2S:Eu3+,Mg2+,Ti4+长余辉材料比较,发现两种方法都可以制备粒度基本相同的纯相Y2O2S基质晶体,但共沉淀法样品的颗粒结构更松散。研究了Eu3+浓度对两种方法制备样品的谱线发射强度的影响,通过比较共沉淀法和高温固相法制备的样品中Eu3+的5D1→7F3较高能级跃迁的587.6nm谱线强度随Eu3+浓度的变化,发现共沉淀法更有利于Eu3+均匀进入Y2O2S基质晶格而形成有效的发光中心。 相似文献
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Red-emitting Y2O3:Eu3+ and green-emitting Y2O3:Tb3+ and Y2O3:Eu3+, Tb3+ nanorods were synthesized by hydrothermal method. Their structure and micromorphology have been analyzed by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The photoluminescence (PL) property of Y2O3:Eu3+,Tb3+ phosphor was investigated. In the same host (Y2O3), upon excitation with ultraviolet (UV) irradiation, it is shown that there are strong emissions at around 610 and 545 nm corresponding to the forced electric dipole 5D0-7F2 transition of Eu3+ and 5D4-7F5 transition of Tb3+, respectively. Different qualities of Eu3+and Tb3+ ions are induced into the Y2O3 lattice. From the excitation spectrum, we speculate that there exists energy transfer from Tb3+ to Eu3+ ions .The emission color of powders reveals regular change in the separation of light emission. These powders can meet with the request of optical display material for different colors or can be potentially used as labels for biological molecules. 相似文献
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Zhongxin Liu Hongwei Song Ruifei Qin Guohui Pan Xue Bai 《Solid State Communications》2006,137(4):199-202
Ag enwrapped Y2O3:Eu3+ nanoparticles were prepared by a wet chemistry method, which was dispersed in liquid (glycol) or dried to powders. Their luminescence properties were studied in comparison to those in the un-enwrapped ones. The results demonstrated that in glycol the 5D0-7F2 transitions for Ag enwrapped Y2O3:Eu3+ nanoparticles became stronger than that for un-enwrapped ones, while the excitation charge transfer band shifted blue. On the contrary, the 5D0-7F2 transitions in Ag enwrapped Y2O3:Eu3+ powders became weaker than those in the un-enwrapped ones. It was suggested that in liquid the Ag shells thinly deposited in the surface of Y2O3:Eu3+ and insulated the Y2O3:Eu3+ from the liquid, which contained large organic vibration modes. As a result, the surface nonradiative energy transfer from Eu3+ to the organic modes decreased, and emission intensity of 5D0-7F2 increased. In the Y2O3:Eu3+ powders, the Ag shells absorbed the excitation light, leading to the decrease in excitation density and the intensity of 5D0-7F2. 相似文献
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Europium (Eu3+) doped YBa3B9O18 were synthesized by conventional solid state solidification methods. (Y1−xEux)Ba3B9O18 formed solid solutions in the range of x=0–1.0. The luminescence property measurements upon excitation in ultraviolet–visible range show well-known Eu3+ excitation and emission. The charge transfer excitation band of Eu3+ dominates the excitation spectra. The emission spectrum of Eu3+ ions consists mainly of several groups of lines in the 550–720 nm region, due to the transitions from the 5D0 level to the levels 7FJ (J=0, 1, 2, 3, 4) of Eu3+ ions. The dependence of luminescence intensity on Eu3+ concentration shows no concentration quenching for fully concentrated EuBa3B9O18. Eu3+ doped YBa3B9O18 are promising phosphors for applications in displays and optical devices. 相似文献
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Zuoling Fu 《Journal of luminescence》2007,124(2):213-216
Y2O3:Eu3+ nanocrystals were prepared by combustion synthesis. The particle size estimated by X-ray powder diffraction (XRD) was about 10 nm. A blue-shift of the charge-transfer (CT) band in excitation spectra was observed in Y2O3:Eu3+ nanocrystals compared with bulk Y2O3:Eu3+. The electronic structure of Y2O3 is calculated by density functional method and exchange and correlation have been treated by the generalized gradient approximation (GGA) within the scheme due to Perdew-Burke-Ernzerhof (PBE). The calculated results show that the energy centroid of 5d orbital in nanocrystal has increasing trend compared with that in the bulk material. The bond length and bond covalency are calculated by chemical bond theory. The bond lengths of Y2O3:Eu3+ nanocrystal are shorter than those of the bulk counterpart and the bond covalency of Y2O3:Eu3+ nanocrystal also has an increasing trend. By combining centroid shift and crystal-field splitting, the blue-shift of the CT band is interpreted. 相似文献
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A nonhydrolytic hot solution synthesis technique was used to grow monodisperse ternary oxide nanocrystals of ZnGa2O4:Eu3+. The shape of ZnGa2O4:Eu3+ nanocrystals was a function of the type of precursor, and their size was controlled by changing the concentration ratio of Zn precursor to surfactant. The crystal structure of synthesized ZnGa2O4 nanocrystals was a cubic spinel with no detectable secondary phases. Photoluminescence of red-emitting ZnGa2O4:Eu3+ nanocrystals resulted in a high (5D0-7F2)/(5D0-7F1) intensity ratio, suggesting that the Eu3+ ions occupy tetrahedral Zn2+ sites or distorted octahedral Ga3+ sites with no inversion symmetry in ZnGa2O4 nanocrystals. 相似文献
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Investigation was performed on luminescent properties of novel Gd2−x
Eu
x
MoB2O9 (0.02≤x≤2.0) phosphors. The excitation spectra consist of broad band and intense narrow lines. The 4f-4f transitions are situated
in a favorable position for excitation by GaN chip emission. The emission spectra consist of transitions from the 5D0 level to the lower 7F manifold, and the emission shows no concentration quenching at higher doping level. The decay time spectra of the 5D0 → 7F2 emission are recorded. Under 395 nm excitation, the intensity of 5D0 → 7F2 transition of GdEuMoB2O9 is 1.2 times stronger than that of commercial Eu3+:Y2O2S phosphor. Gd2MoB2O9:Eu3+ phosphors are promising candidates for near-UV-based solid-state-lighting (SSL). 相似文献
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In the context, Eu3+ (Dy3+)-doped YNbxTa1-xO4 and REVTa2O9 (RE=Y, La, Gd) phosphors have been synthesized from the hybrid precursors. Both XRD and SEM indicated the particles present
good crystalline state, whose crystalline grain sizes were in the range of 0.5 to 1 μm. Besides, XRD patterns of YNbxTa1-xO4 (x=0.1, 0.2, 0.3, 0.5, 0.9) have shown that the phase has been changed from M′-type YTaO4 to M-type YNbO4 with increasing niobium content. Furthermore, from the luminescent spectra of Eu3+-doped YNbxTa1-xO4, it was observed that the 5
D
0–7
F
2 transition of Eu3+ was predominated and its intensity increases with increasing niobium content, as well as the intensity ratio of 5
D
0–7
F
2 transition to 5
D
0–7
F
1 transition for Eu3+. The optimum concentrations of Eu3+ and Dy3+ in YNb0.5Ta0.5O4 have been found to be 6 and 5 mol %, respectively. At the same time, the luminescent properties of Eu3+ and Dy3+ in REVTa2O9 (RE=Y, La, Gd) have also been investigated that GdVTa2O9:Eu3+ (Dy3+) presents high luminescence, while LaVTa2O9:Eu3+ (Dy3+) shows weak luminescence.
PACS 78.20.-e; 78.55.-m; 61.72.Ss; 32.50.+d; 81.40 Tv 相似文献
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Helga Bettentrup Taneli Laamanen Mika Lastusaari Marja Malkamäki Janne Niittykoski Eugeniusz Zych 《Journal of luminescence》2009,129(12):1661-1663
The Y2O3:Eu3+,Mg2+,TiIV materials (xEu: 0.02, xMg: 0.08, xTi: 0.04) were prepared by solid state reaction. The purity and crystal structure of the material was studied with the X-ray powder diffraction. Luminescence properties were studied in the UV-VUV range with the aid of synchrotron radiation. The emission of Y2O3:Eu3+,Mg2+,TiIV had a maximum at 612 nm (λexc: 250 nm) due to the 5D0→7F2 transition of Eu3+. The excitation spectra (λem: 612 nm) showed a broad band at 233 nm, due to the charge transfer transition between O2− and Eu3+, and at 297 nm due to the Ti→Eu3+ energy transfer. Only very weak persistent luminescence was discovered. In the room and 10 K temperature excitation spectra, the line at 208 nm is due to the formation of a free exciton (FE) and a broad band at 199 nm was related to the valence-to-conduction band absorption of the Y2O3 host lattice. The absorption edge was ca. 205 nm giving 6.1 eV as the energy gap of Y2O3. 相似文献