共查询到20条相似文献,搜索用时 15 毫秒
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采用溶胶-凝胶法合成了SrAl2O4:Eu2+,Dy3+纳米长余辉发光材料,利用正交设计法优化了制备工艺.在传统溶胶-凝胶法基础上,添加了硼酸,在950℃生成单一晶相,该法能使SrAl2O4生成温度降低150℃,生成的磷光体发光强度高、余辉时间长,平均晶粒尺寸为25~90nm. 相似文献
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研究了SrAl2O4:Eu^2 ,Dy^3 长余辉材料的一种新合成方法。首先利用水热法制备出该发光材料的前驱体,然后将此前驱体粉体在还原气氛下高温烧结,得亮度高,余辉时间长的洲SrAl2O4:Eu^2 ,Dy^3 超细长余辉材料,并对其发光性能进行了研究。并对水热法和复合沉淀法合成的此种材料进行了比较。 相似文献
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S. B Mishra A. K. Mishra A. S. Luyt N. Revaprasadu K. T. Hillie W. J. vdM Steyn E. Coetsee H. C. Swart 《应用聚合物科学杂志》2010,115(1):579-587
New photoactive composite based on ethyl vinyl acetate (EVA) and SrAl2O4:Eu,Dy or Sr4Al14O25:Eu,Dy were prepared by melt mixing or extrusion methodologies. The phosphorescent behavior and material properties of the polymer‐phosphor composites were studied. The morphology of the polymer and the composites were studied by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X‐ray spectroscopy (EDS). The SEM shows that the physical and chemical behavior of the matrix and the extrusion conditions were primarily responsible for the surface morphology. TEM and EDS show that the phosphor particles were uniformly dispersed in the EVA matrix. A broad band of ultraviolet (UV)‐excited phosphorescence of SrAl2O4:Eu,Dy and Sr4Al14O25:Eu,Dy phosphors and the respective composites were observed at wavelengths of 516 nm and 490 nm, respectively. The photoluminescence (PL) spectra showed less intense phosphorescence but no shift in the wavelength of the emission peak for all the composites. The Hamburg wheel test was done on all the composites and the PL measurements before and after the test showed almost no change in the intensity of the emission. Thermal studies showed that the presence of the phosphors in the matrix slightly increased the crystallinity of EVA, which leads to higher melting enthalpies. Tensile testing shows very little change in the tensile strength and flexibility of the ethylene vinyl acetate copolymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Rebecca J. O’Toole Bola Yoon Christopher J. Gump Rishi Raj Alan W. Weimer 《Journal of the American Ceramic Society》2021,104(6):2472-2482
The addition of small quantities of aluminum oxide (Al2O3) to 8 mol% yttria-stabilized zirconia (8YSZ) benefits conventional sintering by acting as a sintering aid and altering grain growth behavior. However, it is uncertain if these benefits observed during conventional sintering extend to flash sintering. In this work, nanoscale films of Al2O3 are deposited on 8YSZ powders by particle atomic layer deposition (ALD). The ALD-coated powders were flash sintered using voltage-to-current control and current rate experiments. The sintering behavior, microstructural evolution, and ionic conductivities were characterized. The addition of Al2O3 films changed the conductivity of the starting powder, effectively moving the flash onset temperature. The grain size of the samples flashed with current rate experiments was ~65% smaller than that of conventionally sintered samples. Measurement of grain size and estimates of sample density as a function of temperature during flash sintering showed that small quantities of Al2O3 can enhance grain growth and sintering of 8YSZ. This suggests that Al2O3 dissolves into the 8YSZ grain boundaries during flash sintering to form complexions that enhance the diffusion of species controlling these processes. 相似文献
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燃烧法合成长余辉发光材料SrAl2O4:Eu2+,Dy3+的研究 总被引:1,自引:0,他引:1
以尿素和硝酸盐溶液为反应介质,在600℃下用燃烧法一次制备出了Eu^2 ,Dy^3 掺杂的铝酸锶(SrAl2O4)磷光体。用SEM、XRD研究了所得磷光材料的形态、粒度和物相组成,用荧光分光光度计测定了磷光材料的发光性能。结果表明SrAl2O4:Eu^2 ,Dy^3 磷光材料的晶体结构属于单斜晶系结构。制备产物的形貌呈疏松多孔状,晶粒形状为针状,长度有200nm左右,直径在80nm以下。制备产物在520nm处有很强的发射峰,它的激发光谱是激发峰峰值290nm的宽带激发。并探讨了该材料发光性能的影响因素。 相似文献
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Tingsong Li Qiang Liu Danyang Zhu Penghui Chen Yanqiu Jing Junlin Wu Haohong Chen Dariusz Hreniak Martin Nikl Jiang Li 《Journal of the American Ceramic Society》2023,106(10):5877-5886
(Sr0.97Eu0.01Dy0.02)Al2O4 persistent luminescence (PersL) ceramics were fabricated by solid-state reactive sintering in vacuum combined with hot isostatic pressing (HIP) using H3BO3 as a sintering additive. The phase composition, microstructure, luminescence properties, trap state, and PersL performance of HIP post-treated (Sr0.97Eu0.01Dy0.02)Al2O4 PersL ceramics were discussed. For the (Sr0.97Eu0.01Dy0.02)Al2O4 PersL ceramics after HIP post-treatment, the initial luminescence intensity of the ceramics reached over 6400 mcd/m2 with simulated daylight irradiation of 1000 lx for 5 min, and the persistent emission decay time > 17 h. This is much better than the SrAl2O4:Eu2+,Dy3+ PersL powders and the other luminescent ceramics. In addition, this method is a solid-state reactive sintering method for synthesizing ceramics, which has the advantages of low cost and simple operation, and is suitable for large-scale, high-volume industrial production. 相似文献
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采用凝胶-燃烧法合成了LiLa(MoO4)2:Dy3+黄色荧光粉,借助XRD、FE-SEM、荧光光谱仪对样品的晶体结构、形貌、发光特性等进行了分析.结果表明:所得LiLa(MoO4)2:Dy3+样品为四方白钨矿型结构,平均粒径为500 nm左右;样品的发射光谱由位于486 nm较强的蓝光发射、574 nm很强的黄光发射和662 nm较弱的红光发射组成,CIE1931色坐标为(0.3848,0.4341),位于黄光区;Dy3+最佳掺杂量为x=0.025 mol;柠檬酸的最佳加入量为n(NO3-)/n(C6H8O7)=3.0;最佳点火温度为650℃. 相似文献
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利用水热法合成了NaY(WO4)2:Dy3+上转换荧光粉. 通过XRD、SEM表征该荧光粉结构和形貌. 探讨了Dy3+浓度、pH值、反应温度及焙烧温度对NaY(WO4)2:Dy3+晶体结构、形貌及发光性能的影响,得到在Dy3+浓度为0.5%,pH=8,反应温度180℃,800℃焙烧条件下的样品具有最佳上转换发光性能. 利用776 nm近红外光激发NaY(WO4)2:Dy3+,观察到480 nm处的蓝光发射峰以及577 nm处的黄光发射峰. 其中蓝光来自Dy3+离子的4F9/2→6H15/2跃迁,黄光由Dy3+离子4F9/2→6H13/2跃迁产生. 相似文献
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采用原子吸收分光光度法对化学试剂重铬酸铵中钾、钠的含量进行了测定。实验结果表明 ,该法具有准确度高、方法简单、快捷等特点。钾、钠的回收率分别在 95 2 5 %以上 ,RSD分别为 4 %、3%。 相似文献
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Weilun Zhang Yujun Liang Yingli Zhu Shiqi Liu Haoran Li Wen Lei 《Journal of the American Ceramic Society》2019,102(9):5223-5233
A series of Ce3+ and Tb3+ singly- and co-doped NaBa4(AlB4O9)2Cl3 (NBAC) phosphors have been synthesized via high-temperature solid state route. The crystal structure, morphology, photoluminescent properties, thermal properties and energy transfer process between Ce3+ and Tb3+ were systematically investigated. The structure refinements indicated that the phosphors based on NBAC crystallized in P42nm polar space group in monoclinic phase. The emission color could be tuned from blue (0.1595, 0.0955) to green (0.2689, 0.4334) via changing the ratio of Ce3+/Tb3+. The energy transfer mechanism of Ce3+/Tb3+ was verified to be dipole–quadrupole interaction via the examination of decay times of Ce3+ based on Dexter's theory. The good thermal stability showed the intensities of Ce3+ at 150°C were about 66.9% and 64.88% in NBAC:0.09Ce3+ and NBAC:0.09Ce3+, 0.07Tb3+ of that at room temperature, and the emission intensities of Tb3+ remained 102.41% in NBAC:0.11Tb3+ and 95.22% in NBAC:0.09Ce3+, 0.07Tb3+ due to the nephelauxetic shielding effect and the highly asymmetric rigid framework structure of NBAC. The maximum external quantum efficiency (EQE) of Ce3+ in NBAC:0.09Ce3+, yTb3+ phosphors could reach 43.38% at y = 0.13. Overall, all the results obtained suggested that NBAC:Ce3+, Tb3+ could be a promising option for n-UV pumped phosphors. 相似文献
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Rong Tu Yang Yuan Litong Guo Jun Li Song Zhang Meijun Yang Qizhong Li Lianmeng Zhang Takashi Goto Hitoshi Ohmori Ji Shi Haiwen Li 《International Journal of Applied Ceramic Technology》2019,16(6):2265-2272
Aluminum acetylacetonate (Al(acac)3) was used as a precursor to synthesize aluminum oxide (Al2O3) coatings on Ti(C, N)-based ceramic by microwave plasma CVD (MPCVD). Al2O3 coatings transformed from γ phase to δ phase and α phase and as microwave power (pM) and total pressure (Ptot) increased. The effects of pM and Ptot on the microstructure of the Al2O3 coating and oxidation of the substrate have been investigated. The relationship between phase structure and adhesive strength of the coatings was also studied. Coatings deposited at pM = 1.0-1.2 kW and Ptot = 400 Pa exhibited good adhesion strength (Class 1). 相似文献
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Riyanto Edy Xiaojiang Huang Ying Guo Jing Zhang Jianjun Shi 《Nanoscale research letters》2013,8(1):79
In this paper, polyethyleneterephthalate (PET) films with and without plasma pretreatment were modified by atomic layer deposition (ALD) and plasma-assisted atomic layer deposition (PA-ALD). It demonstrates that the Al2O3 films are successfully deposited onto the surface of PET films. The cracks formed on the deposited Al2O3 films in the ALD, plasma pretreated ALD, and PA-ALD were attributed to the energetic ion bombardment in plasmas. The surface wettability in terms of water contact angle shows that the deposited Al2O3 layer can enhance the wetting property of modified PET surface. Further characterizations of the Al2O3 films suggest that the elevated density of hydroxyl -OH group improve the initial growth of ALD deposition. Chemical composition of the Al2O3-coated PET film was characterized by X-ray photoelectron spectroscopy, which shows that the content of C 1s reduces with the growing of O 1s in the Al2O3-coated PET films, and the introduction of plasma in the ALD process helps the normal growth of Al2O3 on PET in PA-ALD. 相似文献