超声喷雾共沉淀法制备纳米铕掺杂钇铝石榴石荧光粉

以NH4HCO3与NH3·H2O的混合溶液为沉淀剂,用超声喷雾共沉淀法获得Eu:YAG粉末先驱体,经一定温度煅烧后得到纳米铕掺杂钇铝石榴石(Eu:YAG)荧光粉。用荧光光谱仪、X射线衍射仪、扫描电子显微镜对粉体的结构、物相组成、颗粒形貌进行了研究。详细地研究了不同铕掺杂浓度粉体的发射光谱和激发光谱特性。结果表明:采用超声喷雾技术能获得大小为50～70nm、颗粒度均匀的Eu:YAG纳米颗粒,与溶胶-凝胶等方法制备的颗粒大小与均匀性相比,显示出一定的优势。同时研究还表明,烧结温度对Eu:YAG荧光粉的析晶有重要影响,随着烧结温度的升高,衍射峰逐渐变窄,衍射强度增大,有利于促进YAG相的生成。因此利用超声喷雾共沉淀法制备红色Eu:YAG荧光粉体是一种有效的途径。     

Yb:YAG与Nd:YAG纳米晶的制备及性能

通过超声-微波辅助醇盐水解沉淀法合成了Yb:YAG与Nd:YAG纳米晶。研究了微波辐射功率、微波辐射时间及煅烧温度对产物的影响。采用X-射线粉末衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)及光致发光谱(PL)等对Yb:YAG与Nd:YAG纳米晶进行表征。结果表明,在微波辐射功率385 W、微波辐射时间30 min、煅烧温度1100 C条件下,可以获得纯相Yb:YAG与Nd:YAG纳米晶。当煅烧温度为1100 C时,Yb:YAG与Nd:YAG纳米晶的合作发光强度均达到最大值。     

Yb:YAG与Nd:YAG纳米晶的制备及性能（英文）

通过超声-微波辅助醇盐水解沉淀法合成了Yb:YAG与Nd:YAG纳米晶。研究了微波辐射功率、微波辐射时间及煅烧温度对产物的影响。采用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)及光致发光谱(PL)等对Yb:YAG与Nd:YAG纳米晶进行表征。结果表明,在微波辐射功率385 W、微波辐射时间30 min、煅烧温度1100oC条件下,可以获得纯相Yb:YAG与Nd:YAG纳米晶。当煅烧温度为1100oC时,Yb:YAG与Nd:YAG纳米晶的合作发光强度均达到最大值。     

用双坩埚硫化法制备Y2O2S∶Eu3+纳米纤维

通过静电纺丝技术制备了PVP/[Y(NO3)3+Eu(NO3)3]复合纳米纤维,在700℃焙烧后得到Y2O3∶Eu3纳米纤维,然后采用双坩埚法硫化Y2O3∶Eu3纳米纤维,得到Y2O2S∶Eu3+纳米纤维,并将其与固-固合成法得到的Y2O2S∶Eu3颗粒进行了比较,证明了双坩埚硫化法是一种重要的硫化方法,既可以在较低的温度下得到纯六方晶系的Y2O2S∶Eu3,又保持了Y2O3∶Eu3纳米纤维的形貌.详细地讨论了双坩埚硫化方法的反应机理.     

纳米晶Cu8SnTe6的合成及半导体性能研究

分别采用微波溶剂热法和溶剂热法合成出纳米晶Cu8SnTe6,并比较得出微波溶剂热法制备的纳米晶晶化效果好,粒径细小.通过化学分析和X射线粉末衍射(XRD)、透射电子显微镜(TEM)及X射线光电子能谱(XPS)等手段表征其组成,研究其结构.讨论了反应时间和有机溶剂填充度等反应条件对该纳米晶产率和粒径的影响,探讨了微波溶剂热法合成机理.紫外可见漫反射光谱(UV-Vis)表明,该纳米晶禁带宽度为1.77 eV,具有优良的半导体性能.     

纳米晶Cu8SnTe6的合成及半导体性能研究

分别采用微波溶剂热法和溶剂热法合成出纳米晶Cu8SnTe6,并比较得出微波溶剂热法制备的纳米晶晶化效果好,粒径细小.通过化学分析和X射线粉末衍射(XRD)、透射电子显微镜(TEM)及X射线光电子能谱(XPS)等手段表征其组成,研究其结构.讨论了反应时间和有机溶剂填充度等反应条件对该纳米晶产率和粒径的影响,探讨了微波溶剂热法合成机理.紫外可见漫反射光谱(UV-Vis)表明,该纳米晶禁带宽度为1.77 eV,具有优良的半导体性能.     

纳米SrAl2O4:Eu,Dy发光特性及浓度猝灭

用溶胶-凝胶法合成了不同Eu2+掺杂浓度的SrAl2O4Eu2+,Dy3+纳米晶体,探讨了纳米晶体的发光性能及浓度猝灭.结果发现纳米晶体与相应的常规尺寸的发光粉末材料相比,发射光谱和激发光谱的主峰位置均出现了明显的蓝移,发光强度和猝灭浓度有明显的提高,余辉衰减速度加快.认为蓝移现象以及余辉衰减变快,主要归因于发光粉体纳米粒子的量子尺寸效应.     

纳米Eu0.12Y1.78La0.10O3-δ荧光粉的合成动力学

利用不同升温速率的差热-热重分析(DTA-TG)研究纳米Eu0.12Y1.78La0.10O3-δ荧光粉的合成动力学。研究表明,纳米Eu0.12Y1.78La0.10O3-δ荧光粉的前驱体为六方相Y(OH)3,利用Doyle-Ozawa法和Kissinger法计算得到前驱体2个分解阶段的表观活化能平均值分别为699.40、362.81kJ.mol-1。用Kissinger法确定反应级数和频率因子,确定纳米Eu0.12Y1.78La0.10O3-δ荧光粉2个合成阶段的反应速率方程分别为dα/dt=1.94×1046e-84120/T(1-α)1.17;dα/dt=5.89×1020e-43640/T(1-α)1.14。     

溶胶-凝胶法制备YAG颗粒及在电接触材料中的应用

以硝酸钇(Y(NO₃)₃6H₂O)、硝酸铝(Al(NO₃)₃9H₂O)为主要原料,六次甲基四胺作为催化剂,采用溶胶-凝胶法合成Y₃Al₅O₁₂(YAG)纳米颗粒,并以YAG颗粒为第二相增强材料,通过粉末冶金工艺制备Ag/YAG电接触复合材料;采用X-射线衍射仪(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM),傅里叶红外光谱(FT-IR)、硬度计、电导率仪等方法对其进行表征。结果表明：在水浴温度为50℃的条件下成功采用sol-gel法合成YAG纳米颗粒,物相纯度高;随着催化剂六次甲基四胺加入量的增加,YAG粉末颗粒粘连在一起,并出现大孔;以YAG为第二相增强材料制备的Ag/YAG电接触复合片材电阻率较低,维氏硬度大于80。     

三元多硒化物的微波溶剂热合成及其结构

以微波溶剂热法制备纳米晶粉体Ag8SnSe6,通过X射线粉末衍射、透射电子显微镜和X射线光电子能谱等手段表征其组成。实验考察了超声波辐照、合成时间和有机溶剂填充度等条件对其产率和粒径的影响。探讨了微波溶剂热法合成纳米晶的机理。漫反射紫外可见吸收光谱(UV-Vis)表明其禁带宽度为2.14 eV,具有优良的半导体性能。     

Phase transition, structure and luminescence of Eu:YAG nanophosphors by co-precipitation method

The methods to synthesize Eu:YAG phosphor by co-precipitation method and solid-state synthesis were compared. The dynamic aspects of the phase transition of Eu:YAG precursor synthesized by co-precipitation method were studied by using X-ray diffraction, infrared and Raman spectroscopy. The results showed that the precursor transformed to pure-YAG phase at the sintering temperature of 900 °C without intermediate phases present. Transmission electron microscope for the precursor powders sintered at 900–1200 °C showed that the powders were well-dispersed and had average size about 50–100 nm.The fluorescence spectra showed that the Eu:YAG phosphors had strong photoluminescence. The luminescence properties of the sintered powders depend on the sintering temperature were also analyzed.     

白光LED用新型Eu或Gd共掺杂的Ce:YAG单晶荧光材料的光谱性能研究

开展了白光LED用新型YAG单晶荧光材料的制备和光谱性能研究,采用提拉法生长Eu,Ce:YAG及Gd,Ce:YAG晶体,并通过吸收光谱,激发、发射光谱及电光性能等对晶体材料的光谱特性进行表征。结果表明,Eu或Gd共掺杂的Ce:YAG单晶荧光材料均可以被波长460nm左右的蓝光芯片有效激发,产生一个范围为480～650nm的宽峰发射。Eu3+或Gd3+共掺杂会对Ce3+离子的发光产生影响:Eu3+离子的掺杂,会对Ce3+离子的发光产生淬灭效应;而Gd3+离子取代基质Y3+离子可以使Ce3+离子的发射峰发生红移。     

化学共沉淀法制备BaAl_2Si_2O_8:Eu~(2+)荧光粉及其发光特性

采用化学共沉淀法一次煅烧工艺制备BaAl2Si2O8:Eu2+荧光粉。用X射线衍射仪、荧光分光光度计和扫描电镜等对BaAl2Si2O8:Eu2+荧光粉的相结构、发光性能、形貌进行表征。结果表明,化学共沉淀法合成了单相的BaAl2Si2O8:Eu2+,且粒度小,分布均匀,呈类球形。在320nm激发下,其发射主峰位于465nm附近,当Eu2+的掺杂浓度为3.5%,发光强度达到最大值,猝灭浓度有所提高,这主要是由于纳米微粒边界对能量共振传递的阻断和猝灭中心在纳米晶内分布的涨落性引起的。     

Synthesis of Y2O3：Eu^3＋ phosphors by surface diffusion and their photoluminescence properties

Y2O3:Eu3+ phosphors were synthesized by the surface diffusion method (SDM). X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to characterize the structure, morphology and component of Y2O3:Eu3+ phosphors. The photoluminescent (PL) properties were also investigated. The results reveal that the PL intensity of Y2O3:Eu3+ phosphors prepared by the surface diffusion method (SDM) is much higher than that prepared by homogeneous co-precipitation. Th...     

等离子喷涂SrAl_2O_4涂层的发光性能

把发光材料稀土铕、镝掺入铝酸锶为喷涂材料,用等离子喷涂法, 将材料喷涂在钢板上.利用X射线衍射、扫描电子显微镜等分析手段对铝酸锶涂层的微观结构进行研究.通过发光光谱对铕、镝掺杂的铝酸锶涂层的发光性能进行表征,并对涂层的发光机制做初步探讨.     

Synthesis of PMA/Eu2O3 porous-layered nanocomposite by in situ polymerization and its morphology

The PMA/Eu2O3 porous and layered nanocomposite was prepared by in situ polymerization and characterized by means of X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscope （SEM）, and inflared ray （IR）. Microscopic investigation of the nanocomposite was carded out by atomic force microscopy （AFM）. The results showed that the shape of the composite was layered and porous. Eu2O3 was grafted when methyl acrylate （MA） polymerized; thus Eu2O3 particles appeared on both sides of the chains of polymeric methyl acrylate （PMA）.     

Structure,Texture and Magnetic Properties of Laser-Welded Ultrathin Fe-Co-V Foils

This research aims to investigate the effect of pulsed Nd:YAG laser micro-welding on the microstructure,texture and magnetic properties of ultra-thin Fe-Co-7.15 wt%V magnetic alloy.Optical microscopy,scanning electron microscopy and electron backscattered diffraction techniques were used to study the microstructural evolutions.Also,vibrating sample magnetometry was used to characterize the magnetic properties.The results showed that the fractions of low Σ coincidence site lattice boundaries in the fusion zone are higher than those of the base metal.The welded samples experience a significant decrease in their magnetic properties.It was found that the formation of new fiber texture in the fusion zone and grain coarsening are the most important factors affecting the magnetic properties.     

Crystallization, morphology and luminescent properties of YAG：Ce^3＋ phosphor powder prepared by polyacrylamide gel method

A novel synthesis process, based on the polyacrylamide gel method, was used to prepare Ce-doped YAG phosphor powders. Effects of heat treatment parameters, temperature and holding time, the fluxes, and atmosphere on microstructure and particle morphology as well as luminescent properties of YAG：Ce^3＋ phosphor powders were studied by X-ray powder diffractometry, scanning electron microscopy, and fluorescence spectrophotometry. The results show that the formation temperature （1 000 ℃） of pure YAG phase is significant low when being synthesized by the polyacrylamide gel method, compared with solid-state reaction. For luminescent properties, the intensity of emission of YAG：Ce^3＋ phosphor increases steadily with increasing temperature from 900 ℃ to 1 300 ℃ and prolonging holding time from 100 min to 400 min. But blue shift phenomenon is observed for 400 min calcination Fluxes as BaF2 and H3BO3 can enhance the intensity of emission of phosphor due to the improvement of crystallization of YAG and the stabilization of trivalence cerium ion in YAG host lattice at high temperature. Weak reduction atmosphere can contribute to improvement of the emission intensity of YAG：Ce^3＋ phosphor powders.