掺铝钕高硅氧玻璃的制备及光谱性能研究

采用分相酸溶工艺制备了Na2O-B2O3-SiO2体系纳米多孔玻璃,并以此为基质进行了钕铝掺杂的实验,制备了掺钕铝高硅氧玻璃,光谱分析表明,所制得的玻璃在1064 nm附近有明显的发射峰.研究了掺杂浓度、烧结气氛对玻璃光谱性能的影响,分析了铝离子在共掺杂玻璃中的作用.结果表明在浓度为0.2 mol/L的Nd(NO3)3溶液中制备的掺杂高硅氧玻璃发光强度最强,还原气氛下烧结的掺杂高硅氧玻璃光谱强度高于在空气中烧结得到的高硅氧玻璃,同时在还原条件下铝离子能够明显的提高玻璃的发光强度.     

高硅氧发光玻璃的制备及其荧光性能

石英玻璃具有低膨胀、耐热冲击、高机械强度和高化学隐定性等优点,是稀土和过渡金属发光离子掺杂的优选的基质材料。但发光离子在石英玻璃中容易自发形成团簇,产生浓度淬灭效应,介绍一种用二氧化硅质量分数超过95%的纳米微孔玻璃来抑制发光离子团簇的自发形成的新方法,以制备高发光强度的石英破璃和激光玻璃。该方法是将发光离子浸入微孔玻璃中并在适当气氛中烧结,目前已经制得多种颜色、量子效率接近于1的强发光玻璃,真空紫外光激发发光玻璃,高铒离子掺杂的高硅氧玻璃,还获得了新颖的低膨胀、耐高温的掺钕高硅氧激光玻璃和掺铋红外宽带发光玻璃用这种方法还容易进行多种发光活性离子掺杂,实现不同离子间的能量转换,提高发光强度和改变激发光的波长范围。这种新方法有望扩大石英发光玻璃的应用范围。     

莫来石－高硅氧玻璃相材料的制备研究

采用一种高岭石类粘土,制备了一种由莫来石和高硅氧玻璃构成的材料,并探讨了不同添加剂对该材料的烧结及其结构、性能的影响。由于高硅氧玻璃相在高温下具有高粘度,以及低温下具有较低的热膨胀系数,故对由该材料制成的耐火制品的高温性能和热震稳定性都是十分有利的。     

用矾土制备莫来石-高硅氧玻璃材料的研究

用Al2O3含量在57％～62％的矾土制备了一种由莫来石与高硅氧玻璃所构成的材料。在高温下，玻璃转变为高粘度的液相对高温性能有利；低温下，由于高硅氧玻璃的热膨胀系数低，莫来石形成交叉网络结构，有利于提高热震稳定性。这是一种有广泛前途的耐火原料，也为我国二级矾土的开发利用开辟了新途径。     

Ce:YAG微晶玻璃制备及光谱性能

在Y2O3-Al2O3-SiO2-Li2O-K2O-Na2O基质玻璃中掺入Ce,经过不同温度热处理,制备出白光LED用Ce∶Y3Al5O12(Ce∶YAG)微晶玻璃.利用X射线衍射仪、X射线光电子能谱仪、场发射扫描电子显微镜、荧光光度计等方法对微晶玻璃的晶相、所掺杂Ce的价态、微观形貌以及光谱性能进行了研究.结果表明:...     

CaO杂质在莫来石-高硅氧玻璃材料中的分布

对M40莫来石-高硅氧玻璃复合材料的杂质及CaO分布进行了分析,发现K2O、Na2O、MgO、Fe2O3和TiO2杂质的大部分进入了玻璃相中,但CaO却以CaSiO3的形式呈点状集中分布于晶相中,HF酸不能将其溶解,而是与其反应生成CaF2。     

莫来石—高硅氧玻璃复相材料的研制

研究了莫来石-高硅氧玻璃复相材料的相组成、显微结构、性能及应用。从相图出发，探讨了该复相材料的制备工艺和几种不同添加剂对制备该复相材料的影响。结果表明，含K2O化合物或矿物为较理想的助熔剂，以高钾矿物为添加剂，以高岭土为原料，制备了不含方石英和刚玉、莫来石含量在55％～60％的莫来石-高硅氧玻璃复相材料，该复相材料的体积密度为2．56g·cm－3，耐火库为1750～1770℃，室温至1300℃的热膨胀系数为4．2×10－6K－1。     

谈结构水对高硅氧布性能的影响

高硅氧布含有大量的结构水,结构水的存在影响高硅氧布SiO_2含量的测定.但经700℃加热处理后,SiO_2含量趋于稳定.当大量结构水除去后,高硅氧布的宽度减小,质量增加,密度增加,强力减小.真空干燥处理过的高硅氧布,结构水含量下降,强力并不下降.     

Spectroscopic Properties and Energy Transfer Mechanism of Er^3＋/Yb^3＋/Ce^3＋ Codoped Tellurite-based Glasses

为进一步揭示多稀土离子共掺低声子能量玻璃中Er3＋的光谱特性及其发光机理,采用高温熔融法制备了Er3＋/Yb3＋/Ce3＋共掺组分为（72.5–x）TeO2–20ZnO–5La2O3–0.5Er2O3–2Yb2O3–xCe2O3（x=0,0.4,0.7,1.0,摩尔分数x%）的碲酸盐玻璃,通过测量吸收光谱、荧光光谱和无掺杂样品的Raman光谱,以及计算相应能级间的吸收截面和受激发射截面,研究并分析了Yb3＋和Ce3＋离子掺杂对于Er3＋的1.55μm波段荧光特性的影响。结果显示：Yb3＋和Ce3＋的引入能显著增强975nm泵浦下Er3＋的1.55μm波段荧光强度。分析表明：Er3＋在1.55μm波段荧光强度的增强主要归结于Yb3＋/Yb3＋、Yb3＋/Er3＋离子间的共振能量传递过程以及基于单声子和双声子辅助的Er3＋/Ce3＋离子间的能量传递过程,并通过计算得到了相应稀土离子间的能量传递微观参数和声子所作的贡献比。     

HGB改性酚醛／高硅氧布复合材料的制备及性能

采用高强中空玻璃微珠(HGB)改性酚醛树脂(PF),制备了PF/高硅氧布/HGB复合材料层压板,研究了HGB含量对复合材料烧蚀性能、密度、隔热性能的影响,同时采用扫描电子显微镜和金相电子显微镜观察了HGB的分布。结果表明,HGB均匀分散在纤维束与纤维束之间的树脂胶液中;适量的HGB可提高复合材料炭化层强度,从而提高复合材料的耐烧蚀能力;当HGB质量分数为5%时,复合材料氧-乙炔线烧蚀率和质量烧蚀率最低,分别为0.091 mm/s和0.0669 g/s,比未添加HGB的降低了35.9%和20.1%;复合材料的密度随HGB含量的增加而降低;综合比热容、热扩散系数和导热系数的分析,当HGB质量分数为5%时,复合材料的综合隔热性能最好。     

The Red-Shift of Ultraviolet Spectra and the Relation to Optical Basicity of Ce-Doped Alkali Rare-Earth Phosphate Glasses

The ultraviolet absorption and emission spectra of Ce³⁺ doped phosphate glasses based on gadolinium and sodium phosphates are studied in the present work. Compared with the cerium-free phosphate glass matrixes, CePO₄ doping shifts the ultraviolet absorption edge of glasses into the longer wavelength because of the 4f–5d absorption transition of Ce³⁺. The emission spectra correlate such red-shift with glass compositions. Explanations are based on variation in the optical basicity of glasses, which corresponds not only to the alkali content but also to the O/P ratio. The latter is proportional to the number of nonbridging oxygen in the oxyanion unit (PO₄), and most likely plays an overwhelming role in the overall optical basicity of glasses.     

Synthesis and Optical Properties of Rare-Earth–Aluminum Oxide Glasses

Single-phase glasses containing 37.5 mol% Y₂O₃, 7 mol% La₂O₃, and 1 mol% Pr, Ho, Nd, Er, Sm, Tm, Eu, or Yb oxide substituted for part of the Y₂O₃ were synthesized by containerless melting. The spectral transmission and absorption cross sections of the glasses were determined at wavelengths from 360 to 3300 nm. The electronic transitions were broadened compared with results obtained in a crystalline yttrium aluminum garnet (YAG) host. The infrared transmission of the host glass extended to 6000 nm. The optical and physicochemical properties of these glasses are well suited for optical device applications.     

Electrical Properties of Cerium-Doped BaTiO3

The high-temperature equilibrium electrical conductivity of Ce-doped BaTiO₃ was studied in terms of oxygen partial pressure, P (O₂), and composition. In (Ba_1−xCe _x )TiO₃, the conductivity follows the −1/4 power dependence of P (O₂) at high oxygen activities, which supports the view that metal vacancies are created for the compensation of Ce donors, and is nearly independent of P (O₂) where electron compensation prevails at low P (O₂). When Ce is substituted for the normal Ti sites, there is no significant change in conductivity behavior compared with undoped BaTiO₃, indicating the substitution of Ce as Ce⁴⁺ for Ti⁴⁺ in Ba(Ti_1−yCe _y )O₃. The Curie temperature ( T _c) was systematically lowered when Ce³⁺ was incorporated into Ba²⁺ sites, whereas the substitution of Ce⁴⁺ for Ti⁴⁺ sites resulted in no change in this parameter.     

Properties of Yttria-Aluminoborate Glasses

In the Y₂O₃–Al₂O₃–B₂O₃ system, homogeneous glasses were obtained from compositions containing from 50 to 65 mol% B₂O₃. The density, refractive index, and thermal expansion increase as Y₂O₃ replaces either B₂O₃ or Al₂O₃. These glasses have a dilatometric softening temperature above 665°, and below 300°C their dc electrical resistivity exceeds that of fused silica. The infrared absorption spectra indicate that BO₃, BO₄, and AlO₄, groups are present in these glasses.     

Sol–Gel Synthesis of Cadmium Telluride-Microcrystal-Doped Silica Glasses

The sol–gel process has been applied to the preparation of small-sized CdTe-doped silica glasses. Gels synthesized by the hydrolysis of a complex solution of Si(OC₂H₅)₄, Cd(CH₃COO)₂· 2H₂O, and Te were heated from 350° to 600°C in a H₂─N₂ atmosphere to form fine cubic CdTe crystals. The size of CdTe crystals, determined from the line broadening of X-ray diffraction pattern, increases from 4 to 9 nm in diameter with increasing heat-treatment temperature. The optical absorption edge shifts to the higher-energy side as the size of the CdTe crystals decreases. This phenomenon is interpreted in terms of a quantum confinement effect of electron and hole in the CdTe microcrystals.     

Properties and Structure of Lead Halosilicate Glasses

The glass transformation temperature, thermal expansion coefficient, dc electrical conductivity, and IR transmission have been measured for four series of lead halosilicate glasses of the general composition (65– x )PbO· x PbX₂·35 SiO₂ (X=F, Cl, Br, I). Although results of these and other measurements suggest that the halide ions play similar structural roles in the glass, there appear to be significant differences in physical property behavior between glasses containing F⁻ anions and those containing the other three halide anions. These results are explained by a proposed model incorporating both bridging and nonbridging halide species.     

Preparation and Nonlinear Optical Properties of Quantum-Sized CuCl-Doped Silica Glass by the Sol–Gel Process

The sol–gel process has been applied successfully to the preparation of small-sized CuCl-doped silica glass with a significant quantum-sized effect. Gel synthesized by the hydrolysis of a complex solution of Si(OC₂H₅)₄ and CuCl with an HCl catalyst is heated to 900°C to form fine, cubic CuCl crystals. Above 700°C, absorption peaks observed at ∼370 and ∼380 nm are attributed to the excitation of confined Z_1,2 and Z₃ excitons, respectively, in the CuCl microcrystals. As the size of the CuCl crystals decreases, exciton energy shifts to the higher-energy side. The resonant third-order nonlinear susceptibility at 77 K is 1.1 × 10⁻⁸ esu, which originates from the enhancement by the quantum-sized effect of the exciton.     

Properties of Nitrogen-Containing Yttria—Alumina—Silica Melts and Glasses

The viscosity and solubility of nitrogen in Y₂O₃–Al₂O₃–SiO₂ melts have been systematically examined. The effects of nitrogen content on viscosity for Y-Al-Si-O-N melts and on Vickers hardness of oxynitride glasses also have been examined. Although the viscosity of Y₂O₃–Al₂O₃–SiO₂ melts was decreased, the solubility of nitrogen into the melts was increased with increased Y₂O₃ content. These results indicated that the yttrium ion behaved as a network modifier. Therefore, the structural units for viscous flow became small, and the amount of nonbridging oxygen increased in the melts when the Y₂O₃ content increased. The viscosity of Y-Al-Si-O-N melts and Vickers hardness of oxynitride glasses remarkably increased with increased nitrogen content. These results suggested that the substitution of nitrogen for oxygen in the melts may have led to a high average coordination of nonmetal atoms and that the increased cross-linking produced a more rigid glass network.