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SrZrO3基质氧化物粉体的水热合成和表征 总被引:2,自引:0,他引:2
用水热晶化法制备了SrZrO3纯相和SrZr1-xMxO3-α(M=Al、Ga、In;x≤0.20)体系氧化物,通过XRD、SEM、IR^27Al MASNMR和化学分析,对产物的物相、粒度和所掺杂质进入晶格的数量进行了表征。结果表明,产物为正交结构钙钛矿、粒度为5 ̄15μm,在0≤x≤0.20范围内,产物的金属离子比与投料基本一致。 相似文献
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以La_2O_3、Dy_2O_3、浓HNO_3、偏钒酸钠、氢氧化钠、无水乙醇、乙二醇为原料,采用十六烷基三甲基溴化铵(CTAB)辅助水热法合成了四方晶系锆石结构的LaVO_4∶Dy~(3+)棒状纳米晶体。并用X粉末衍射(XRD)、扫描电镜(SEM)、红外光谱(FT-IR)和荧光光谱(FL)对产品进行了表征和分析。测试结果表明,所得样品为四方锆石型结构,反应pH从7升至10,纳米棒增长60~70nm。LaVO_4∶Dy~(3+)纳米棒分别在574nm和484nm处有较强的黄光发射(~4F_(9/2)→~6H_(13/2))和蓝光跃迁(~4F_(9/2)→~6H_(15/2)),通过改变反应的pH和Dy~(3+)掺杂量达到对黄蓝光强度比值(Y/B)的有效调控,Y/B值最大达1.207。 相似文献
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纳米羟基磷灰石粉体的水热合成 总被引:1,自引:0,他引:1
采用Ca(NO3)2·4H2O和(NH4)3PO4·3H2O作为反应前驱物,通过水热合成颗粒尺寸在100nm以下的短棒状或针状HA晶体.X射线衍射(XRD)、透射电镜(TEM)和红外光谱(FTIR)分析讨论水热温度、反应时间、表面活性剂和烧结与物相组成、晶粒尺寸和晶体形貌的关系.实验结果表明升高反应温度和延长反应时间有利于HA的生成;表面活性剂有助于改善粉体的分散性能;烧结能提高晶体的结晶程度,但粉体易团聚,当温度高于800℃时HA发生分解. 相似文献
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讨论了不同的Mg、Al源为起始反应物、反应温度、时间和碱度对水热合成Mg-Al水滑石物相组成和晶粒度的影响. 用XRD、SEM对合成产物进行了表征, 用X射线全谱拟合法计算了Mg-Al水滑石晶粒度. 以MgO和Al(OH)3为起始反应物, Mg/Al=2,在140℃反应4~10h, 可以制备出高结晶度的单相纳米晶Mg-Al水滑石. Mg-Al水滑石的形成机理可概括为: 水解反应-沉淀成核-晶粒长大. 反应物类型及合成条件会影响前驱物的水解速率和水解程度, 进而影响晶体成核和生长速率,控制物相的组成和晶粒度大小. 相似文献
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Fe(OH)3中微量金属离子对水热合成α—Fe2O3粒径的影响 总被引:3,自引:0,他引:3
本文研究了某些金属离子(Al^3+、Mn^2+、Zn^2+、Cr^2+、Ni^2+、Co^2+)Fe(OH)3凝胶经水热法合成的α-Fe2O3微粉颗粒大小的影响。研究结果出现,随着金属离子的浓度在一定范围内(0.010-0.050mol·L^-1)的增加,α-Fe2O3颗粒有减小的趋势。其中加入Co^2+(0.050mol·L^-1)、Mn^2+(0.100mol·L^-1)可以得到粒径为75nm 相似文献
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In this work, two Tb3+ activated green phosphors: Y2O3:Tb3+ and YBO3:Tb3+ were prepared by hydrothermal method. Photoluminescence properties of both phosphors were studied in details. Both phosphors exhibit similar luminescent characteristics symbolized by the dominant green emission at 545 nm. Concentration quenching occurs at the Tb3+ concentration of 1.60 atomic% and 2.57 atomic% for Y2O3:Tb3+ and YBO3:Tb3+, respectively. Luminescence decay properties were characterized to better understand the mechanism of concentration quenching. Based on the calculation, the concentration quenching in both phosphors was caused by the dipole–dipole interaction between Tb3+ ions. 相似文献
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The rare-earth sesquioxides (RE2O3, RE = Lu, Y and Sc) are very promising host crystals for advanced laser diode (LD)-pumped Yb3+-doped solid-state lasers due to unusual combination, almost unique of favourable structural, thermal and spectroscopic properties which are described. In spite of these favourable properties, the bulk single crystal growth technology for the rare-earth sesquioxides has not been established yet. The extremely high melting temperature at around 2400 °C has prevented it. However, we shall show that yttrium oxide crystals (YbxY1−x)2O3, x = 0.0, 0.005, 0.05, 0.08 and 0.15 of cylindrical shape as laser rods with 4.2 mm in diameter and 15-20 mm in length have been grown from rhenium crucibles by the micro-pulling-down method. The crystal quality characterisation of undoped Y2O3 crystal was determined using X-ray rocking curve (XRC) analysis. Yb were homogeneously distributed in Y2O3 host crystal. 相似文献
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Forming core–shell-structured phosphor particles is an effect way to improve the properties of the rare-earth-doped inorganic luminescent systems, as well as to achieve a reduction in the amount of expensive rare earth metal. Heterogeneous nucleation processing is a commonly used method to prepared core–shell-structured particles. A nanocomposite BaSO4/Y2O3:Eu3+ powder was prepared by coating BaSO4 submicrospheres with nano-Y2O3:Eu3+ particles via heterogeneous nucleation processing. Thermogravimetric analysis and differential scanning calorimetry (TGA/DSC) were utilized to reveal the mechanism of the homogenous precipitation reaction process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) were utilized to characterize the BaSO4/Y2O3:Eu3+ core–shell-structured phosphor particles. By controlling the hydrolysis of urea, BaSO4 particles are well coated with the shell of Y2O3:Eu3+, and the nucleation of coating materials is predominantly heterogeneous rather than homogeneous. Photoluminescence spectra were utilized as well. The BaSO4/Y2O3:Eu3+ particles show a red emission corresponding to 5D0–7F2 of Eu3+ under the excitation of ultraviolet. 相似文献
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Single crystals of Y2Cu2O5 were obtained in the flux growth process by controlled heating of a mixture of Y2O3, BaO, and CuO in a molar ratio of 1820. These crystals were analyzed by a single-crystal X-ray diffraction analysis. The crystal contains polymeric chains of Cu2O5 interspersed by yttrium ions surrounded by octahedral arrangements of oxygen atoms. Crystal data: space group=Pna21,a=10.799(2) Å,b=3.4990(5) Å,c=12.459(2) Å,Z=4, 380 reflections,R=0.026,R
w=0.030. 相似文献
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Oleic-acid-coated CoFe2O4 nanoparticles were synthesized by co-precipitation and hydrothermal synthesis. The coprecipitation of the nanoparticles was achieved by the rapid addition of a strong base to an aqueous solution of cations in the presence of the oleic acid surfactant, or without this additive. The nanoparticles were also synthesized by a hydrothermal treatment of suspensions of the precipitates, coprecipitated at room temperature in the presence of the oleic acid, or without it. The influence of the synthesis conditions, such as the valence state of the iron cation in the starting aqueous solution, the temperature of the treatment and the presence of oleic acid, on the particles size was systematically studied. X-ray powder diffractometry (XRD) and transmission electron microscopy (TEM) coupled with energy-dispersive X-ray spectroscopy (EDS) revealed that, although spinel forms at room temperature, a substantial amount of Co was incorporated within the secondary, feroxyhyte-like phase when the iron cation was in the 2+ state. In contrast, when iron was in the 3+ state, the spinel forms at elevated temperatures of approximately 60 °C. The presence of the oleic acid further increased the formation temperature for the stoichiometric spinel. Moreover, the oleic acid impeded the particles’ growth and enabled the preparation of colloidal suspensions of the nanoparticles in non-polar organic solvents. The nanoparticles’ size was successfully controlled by the temperature of the synthesis in the region where superparamagnetism dominates to the region where mono-domain ferrimagnetism dominates the magnetic properties. 相似文献
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Monodisperse BaTiO3 powder was prepared by a hydrothermal process from a mixture of Ba(OH)2 and Ti(OH)4. In the process, the best synthesis conditions were a Ba(OH)2/Ti(OH)4 mole ratio of 1, the reaction temperature 180°C, which produced the cubic crystal structure of BaTiO3 with 0.3 m size. The effects of synthesis conditions and the dispersion stability of powder were investigated. The reaction kinetics was also discussed from the experimental results. 相似文献
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A structural study of the rhombohedral compound 3Y2O3, WO3 doped with Europium was carried out. The fluorescence spectrum of Eu3+ was measured in the frequency range 12500–25000 cm?1. Transitions from the excited state 5D0 to the Stark components of the five lowest 7FJ (J=0,1,2,3,4) states were observed. The analysis revealed that the rare earth ion is within a crystal field of C1 symmetry. We found values for the Bkq parameters which give a good agreement between the observed and calculated levels. 相似文献
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Y. Tsukuda 《Materials Research Bulletin》1981,16(4):453-459
Black Y2O3 pieces are obtained by heating in a reducing atmosphere, and they have some properties other types of Y2O3 do not have. In this study, hardness, transmittance and thermoluminescence of black Y2O3 sintered pieces are investigated.The Knoop hardness numbers of the black Y2O3 pieces vary from 615 to 804 kg/mm2, and the average hardness number is 699 kg/mm2, which is nearly equal to that of a colorless piece. In-line transmittances of the dark Y2O3 pieces in the 0.2~11 μm wavelength are lower than those of colorless pieces. The trap level of the black Y2O3 pieces is 1.22 eV. 相似文献
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Y2O3与Gd2O3共掺杂SrZrO3热障涂层材料的热物理性能 总被引:1,自引:0,他引:1
采用固相反应法合成了5mol%Y2O3与5mol%Gd2O3共掺杂SrZrO3(Sr(Zr0.9Y0.05Gd0.05)O2.95,SZYG)粉末.采用X射线衍射(XRD)和差示扫描量热仪(DSC)分别研究了SZYG粉末在1450℃长期热处理后以及200~1400℃范围内的相稳定性.采用高温热膨胀仪测量了SZYG块材的热膨胀系数,结果表明:通过Y2O3与Gd2O3共掺杂改性可以明显抑制SrZrO3的相转变.在1000℃下SZYG块材的热导率是~1.36 W/(m.K),与SrZrO3和8YSZ块材相比降低~35%SZYG分别与8YSZ和Al2O3在1250℃热处理24 h表现出很好的化学相容性. 相似文献