Al2 O3对硼硅酸盐玻璃结构和性能的影响

硼硅酸盐玻璃具有优良的抗热冲击性能和优异的光学性能。主要探讨了Al2 O3对硼硅酸盐玻璃的结构和性能的影响。通过红外光谱测试分析了Al2 O3含量不同时玻璃的结构变化,测试了玻璃的热膨胀系数,转变温度、膨胀软化温度、粘度和化学稳定性。研究结果表明：Al2 O3的加入使得玻璃结构中[ BO4]减少,[ BO3]相应增加,从而使得玻璃结构疏松。玻璃的热膨胀系数增大,Tg 和膨胀软化点Td 降低,化学稳定性减弱;但玻璃的软化点Tf 在Al2 O3含量小于3%时,随Al2 O3含量增加有降低趋势,大于3%时随Al2 O3含量增加有增大的趋势。玻璃的高温粘度随Al2 O3的加入增大,但低温粘度减小。     

硼硅酸盐玻璃结构与其熔体性质研究

对硼硅酸盐玻璃结构及其熔体性质展开研究,通过红外光谱分析了Al2O3对硼硅酸盐玻璃结构的影响,测试了玻璃熔体的高温粘度和抗折强度.研究结果表明:当玻璃中Al2O3/SiO2物质的量比在1.2％～6.5％,(R2O-Al2O3)/B2O3的物质的量比在0.04 ～0.41范围内时,Al3+全部以[AlO4]形式存在,是玻璃网络形成体,B3+大部分以[BO3]的形式存在,是玻璃网络外体,少部分以[BO4]形式存在,是玻璃网络形成体.增加玻璃熔体中Al2O3的含量,玻璃中游离氧含量和[BO4]含量减少,[BO3]含量增加,玻璃的高温粘度增大,熔制温度升高,抗折强度降低.     

Al2O3对硼硅酸盐玻璃热膨胀和分相的影响

通过红外光谱分析了Al2O3取代SiO2后硼硅酸盐玻璃结构的变化,测试了玻璃的热膨胀系数和膨胀软化温度,通过扫描电子显微镜分析硼硅酸盐玻璃的分相,并结合X射线能谱分析了富硅相的组成.结果表明:硼硅酸盐玻璃中引入Al2O3后,随着Al2O3取代量的增加,玻璃结构中[BO3]增多,[BO4]减少;玻璃的热膨胀系数增大,转变温度和软化温度提高;硼硅酸盐玻璃中引入Al2O3后对玻璃的分相没有明显的改善作用.     

Na2O-B2O3-SiO2玻璃结构中硼配位状态的研究

本文主要探讨玻璃熔体在不同的温度处理情况下对硼硅酸盐玻璃结构的影响.通过红外光谱和核磁共振谱分析了硼硅酸盐玻璃在不同温度处理情况下的结构变化.研究结果表明:硼硅酸盐熔体从高温冷却下来,硼配位发生由三角体到四面体的转变,并且硅氧网络聚集导致Q3的含量降低.运用NMR研究温度与硼硅酸盐熔体结构关系发现,高温有利于[BO3]及Q3的存在,反之,低温状态下[BO4]以及Q4的比例更高.     

Sm2O3掺杂对BaO-B2O3-Al2O3-SiO2玻璃形成及结构的影响

借助魔角旋转核磁共振技术,探讨掺Sm2O3后BaO-B2O3-Al2O3-SiO2(BBAS)玻璃(BBASS玻璃)的形成、结构及热处理条件下玻璃结构的变化情况.研究表明:随着稀土掺量的增加,BBASS玻璃的形成区域先扩大后缩小.在Sm2O3外掺摩尔分数为30%时BBASS玻璃具有最大的形成区域.在BBAS玻璃结构中,随着BaO含量的增加,硼氧三角体[BO3]逐渐向[BO4]转变,原先[AlO4],[AlO5],[AlO6]共存的铝氧多面体结构逐渐转变为大量[AlO4]和少量[AlO5]共存的结构.在BBASS玻璃结构中,随着5m2O3掺入量的增加,Sm2O3对铝氧多面体结构变化的影响与BaO类似;对硼氧多面体而言,Sm3 强大的积聚作用使玻璃结构中硼氧多面体形成了巨大的网络.以上差异说明了Al3 比B3 更容易进入稳定的四面体结构.热处理对玻璃结构影响甚微.     

n(B2O3)/n(SiO2)对硼硅酸盐玻璃结构和性能的影响

采用热膨胀仪、扫描电镜和红外光谱仪研究了硼硅酸盐玻璃的结构与性能随n(B2O3)/n(SiO2)和n(B2O3)/n(Na2O)的变化规律,深入探讨了结构对分相、热膨胀系数和膨胀软化温度的影响规律。结果表明:热膨胀系数取决于玻璃中[BO3]、[BO4]和[SiO4]的数量变化;玻璃的转变温度和软化温度主要由SiO2决定;[BO3]对玻璃的分相有着重要的影响;不论n(B2O3)/n(Na2O)比值多少,玻璃结构中均存在[BO3]和被破坏的[SiO4]。     

ZrO2对中硼硅医药玻璃结构与性能的影响

采用熔融冷却法制备中硼硅医药玻璃,以ZrO2等质量替代Al2O3.通过红外光谱分析玻璃结构,测试玻璃密度、热膨胀系数、高温粘度以及化学稳定性.研究结果表明:随着ZrO2替代Al2O3质量增加,玻璃结构中[BO3]增多,[BO4]减少,密度逐渐增加,玻璃的热膨胀系数先增大后减小;高温粘度呈现先降低后增大趋势,ZrO2增加对玻璃颗粒耐水和耐酸性能影响不大,而对玻璃颗粒耐碱性能有显著提升作用.     

ZrO_2对Na_2O-B_2O_3-SiO_2玻璃结构及特殊色散性能的影响

硼基特殊色散玻璃中影响相对色散偏离值的主要为玻璃内[BO3]的含量。增加玻璃中[BO3]的含量,可有效增大玻璃的相对色散偏离值,进而提高特殊色散性能。本文按x ZrO_2-(100-x)/100[28Na_2O-36B_2O_3-36SiO2](0mol%≤x≤18mol%)进行了玻璃制备,并通过折射率测试、核磁共振光谱和拉曼光谱技术研究了在SiO_2-B_2O_3-Na_2O系统玻璃中添加不同含量ZrO_2对玻璃结构及特殊色散性能造成的影响。Zr4+具有高场强,可导致网络内过配位氧的增加,促进[BO4]向[BO3]的转变,从而增大相对色散偏离值。     

SiO2-A12O3-MgO玻璃纤维结构与性能-MgO/(Li2O+B2O3)的影响

以不同含量的氧化锂、氧化硼、氧化镁成分的SiO_2-A1_2O_3-MgO高强(HS)玻璃为研究对象,测试了HS玻璃纤维密度、纤维新生态强度和模量,以及浸胶纱的拉伸强度和模量。采用高温粘度旋转仪、梯度炉以及红外光谱(IR)、核磁共振(NMR)等方法,研究了玻璃中不同比例的MgO/(Li_2O+B2O3)对高强玻璃结构和性能的影响。玻璃成分中SiO_2和Al_2O_3含量相近,增大Li_2O和B2O3含量替代MgO含量可以使玻璃的低温粘度和液相温度均降低,而增加MgO含量则提高了离子堆积密度和玻璃纤维的模量。红外光谱及核磁共振分析表明,HS高强玻璃的结构主要由硅氧四面体[SiO_4]和铝氧四面体[AlO_4]构成。在玻璃结构中,增加Li_2O和B2O3含量可提供的游离氧可使更多的Al~(3+)形成[AlO_4]而进入玻璃网络。相应地,增加MgO含量,提高MgO/(Li_2O+B_2O_3)比例,增加了网络断键和无序度,但增大了断网间的集合程度,有利于玻璃模量的提升。研究表明提高玻璃中SiO_2含量或在玻璃中加入Li_2O,有利于SiO_2-A12O3-MgO系统玻璃纤维强度的提升。     

P2O5对Bi2O3-B2O3-ZnO体系玻璃结构及热性能的影响

采用传统的熔融冷却的方法制备了(40-x)Bi2O3-30B2O3-30ZnO-xP2O5(0≤x≤15mo1％)体系玻璃.使用红外光谱、拉曼光谱、DSC和热膨胀仪研究了封接玻璃的结构和热性能.红外光谱及拉曼光谱结果表明,P2O5作为网络形成体,以[PO4]进入到玻璃的网络结构中,玻璃的网络结构性增强.玻璃结构中[BO3]三角体结构单元相对含量有增多趋势,[BO4]四面体、[BiO3]三角体、[BiO6]八面体结构单元相对含量减少.随着P2 O5含量的增加,玻璃化转变温度和玻璃的初始析晶温度升高;玻璃的密度减小.Bi2O3-B2O3-ZnO-P2O5体系封接玻璃热膨胀系数减小,从8.289×10-6℃-1减小到6.354×10-6℃-1.玻璃的软化点逐渐增大,从416℃升高到524℃.     

钕-铝系稀土色料的研制

通过钕-铝系列色料合成实验,分析不同配比及不同矿化剂等对色料呈色效果的影响,确定最佳工艺方法。对实验结果进行XRD及色度分析,确定其主晶相为钕酸铝,试样的明度均在70以上,色彩鲜艳亮丽。     

Na2O-Al2O3-Fe2O3系烧结过程中铝、铁的反应行为

以Al2O3, Fe2O3和Na2CO3为原料,对Na2O-Al2O3-Fe2O3系烧结过程中的反应行为进行了详细研究. 基于溶出率与时间、温度的关系,证明Na2O×Al2O3和Na2O×Fe2O3的生成反应动力学都服从Zhuralev-Lesokin-Tempelman模型,表观活化能分别为186.59和80.92 kJ/mol,表明Na2O×Fe2O3比Na2O×Al2O3在动力学上更易形成;Al2O3易与Na2O×Fe2O3反应形成Na2O×Al2O3和Fe2O3,在1273 K烧结30 min,所得熟料Al2O3溶出率达98.51%;Fe2O3对Na2O×Al2O3的形成有双重作用,在1273 K下可加速Na2O×Al2O3的形成,超过1323 K,促使Na2O×Al2O3分解成Na2O和b-Al2O3,且随着温度升高或时间延长,分解程度增高,从而导致熟料中Al2O3溶出率显著降低.     

Polycrystalline In2O3 and In2O3/Y2O3 photoanodes

Single crystal In₂O₃ shows promise as a photoanode for the decomposition of water. Because of various difficulties in the preparation of the single crystal material, two simple techniques were developed for the preparation of polycrystalline In₂O₃ anodes. One method involves the thermal decomposition of the nitrate while the other utilizes the chemical vapour deposition technique. Voltammograms and photoresponse spectra of these anodes are compared to the single crystal material. Among other observations, it is noted that the quantum efficiencies of the thermally decomposed films are comparable to the single crystal material. It is also shown that the on-set potential can be shifted to more negative values by forming the mixed oxide In₂O₃/Y₂O₃.     

Phase equilibrium in binary La2O3-Dy2O3 and ternary CeO2-La2O3-Dy2O3 systems

Cerium oxide doped with oxides of rare earth elements is a multifunctional material, a wide range of uses which is associated with its unique physicochemical properties. Phase diagrams of multicomponent systems are the physicochemical basis for the creation of new materials with improved characteristics.In this work, phase equilibria in ternary CeO₂–La₂O₃–Dy₂O₃ and binary La₂O₃–Dy₂O₃ systems in the whole concentration range were studied. No new phases have been identified in these systems. An isothermal section of the phase diagram of the CeO₂–La₂O₃–Dy₂O₃ system at a temperature of 1500 °С is constructed. No new phases have been detected in the system. It was found that in the studied ternary system solid solutions are formed on the basis of (F) modification of CeO₂ with structure of fluorite type, monoclinic (B), cubic (C) and hexagonal (A) modifications of Ln₂O₃.In the La₂O₃–Dy₂O₃ binary system (1500–1100 °С) three types of solid solutions are formed: based on hexagonal modification A-La₂O₃, monoclinic modification B-Dy₂O₃ and cubic modification C-Dy₂O₃ separated by two-phase fields (A+B) and (B+C), respectively. The boundaries of the regions of homogeneity of solid solutions based on A-La₂O₃ are determined by compositions containing 35–40, 20–25, 15–20 mol% Dy₂O₃ at 1500, 1250, 1100 °C, respectively. From the obtained data it follows that the solubility of Dy₂O₃ in the hexagonal modification of lanthanum oxide is 39 mol% at 1500 °C, 23 mol. % at 1250 °C and 16 mol% at 1100 °C. The limits of existence of solid solutions based on monoclinic B-modification are determined by compositions containing 30–35, 65–60 (1250 °С), 35–40, 55–60 (1100 °С) 40–45, 70–75 (1500 °C) mol% Dy₂O₃.In the studied system, with a decrease in temperature from 1500° to 1100°C, there is a decrease in the solubility of La₂O₃ in the crystal lattice of cubic solid solutions of C-type from 16 to 10 mol%.     

Fe2O3-MnO-Cr2O3-La2O3系统紫色颜料的制备及表征

采用溶胶均匀共沉淀法于低温下合成了含少量稀土氧化物La2O3的紫色颜料，并采用颜色测定、SEM、XRD等手段对颜料的颜色、检度及结晶构造等进行了表征。     

Separation of Phases by Spinodal Decomposition in the Systems Al2O3−Cr2O3 and Al2O3−Cr2O3−Fe2O3

Separation of phases was investigated in the hexagonal (rhombohedral) systems Al₂O₃−Cr₂O₃ and Al₂O₃−Cr₂O₃−Fe₂O₃. The binary system shows a miscibility gap with a T_c of 950°C; the miscibility gap for the ternary system was determined for a constant Cr₂O₃ content of 16.6 mol%. Dark field transmission electron microscopy of solid solutions annealed within the miscibility gap showed dark and light lamellas ∼50 to 200 Å thick. X-ray diffraction results for the solid solutions in the ternary system indicated that, in the early stages of annealing, broadening occurred only on (hkl) reflections where l≠0. There was no major change in the X-ray diffraction patterns of the annealed solid solutions in the binary system. Electron diffraction results indicated, however, that phase separation in both systems proceeded in the [001] direction. Solid solutions in the binary system separated very slowly; the separation could be enhanced hydrothermally. The mechanism of the separation of phases in both systems is spinodal and proceeds as follows: solid solution→intermediate modulated phase→equilibrium phases.     

Bactericidal Effectiveness of O3, O3/H2O2 and O3/TiO2 on Clostridium perfringens

The purpose of this research is to evaluate the bactericidal capacity of different Advanced Oxidation Treatments (AOTs) based on ozone: ozone, ozone/hydrogen peroxide and ozone/titanium dioxide on a wild strain of Clostridium perfringens, a fecal bacterial indicator in drinking water. The dose of ozone consumed ranges from 0.6 mg L^?1 min^?1 to 5.13 mg L^?1 min^?1 depending on the process and on the sample. In the treatments combined with O₃, H₂O₂ dose utilized is 0.04 mM and TiO₂ dose, 1 g L^?1. In order to evaluate the influence of natural organic matter and suspension solids over the disinfection rate, treatments are performed with two types of water – natural water from Ebro River (Zaragoza, Spain) and NaCl solution 0.9%. To achieve 4 log units of inactivation, 3.6 mg O₃ L^?1 is necessary in O₃ treatment, 4.25 mg O₃ L^?1 in O₃/TiO₂ system and 2.7 mg O₃ L^?1 in O₃/H₂O₂ after processing the natural water. In NaCl solution, to get the same inactivation, 0.42 mg O₃ L^?1 is necessary in O₃ treatment, 1.15 mg O₃ L^?1 in O₃/TiO₂ system and 0.06 mg O₃ L^?1 in O₃/H₂O₂ process. Even though the three treatments studied have a high bactericidal activity due to the number of surviving bacteria decreases to non-detectable levels, O₃/H₂O₂ is the most effective system for eliminating C. perfringens cells in a lower contact time, followed by O₃ and finally O₃/TiO₂ system.     

Properties of RO-Y2O3-Al2O3-SiO2 glasses

The coefficient of linear expansion, glass-transition temperature, temperature at the orset of deformation (strain point), density. Young modulus, microhardness, crystallizability, and contact angle are studied as a function of the composition in RO–Y₂O₃–Al₂O₃–SiO₂ (R=Ca and/or Mg) glass systems. The composition ranges for glasses (with strain point >900°C and coefficient of linear expansion of (32–45)×10^–7°C^–1) that can be used for soldering silicon-nitride ceramics were established.Translated from Steklo i Keramika, No. 12, pp. 5–7, December, 1996     

Cr_2O_3-Al_2O_3砖中不同组成Cr_2O_3-Al_2O_3电熔颗粒料的抗侵蚀研究

首先以不同比例的铬绿和氧化铝粉电熔制得Cr2O3质量分数分别为15%、40%、50%、60%、85%、99%的6种Cr2O3-Al2O3电熔颗粒料(其编号依次为CR15、CR40、CR50、CR60、CR85和CR99),然后采用回转渣蚀法研究了此电熔颗粒料(4~1 mm)的抗侵蚀性。结果显示:电熔颗粒料的抗侵蚀性随Cr2O3含量的增加及颗粒尺寸的增大而增强;高Cr2O3含量的CR99、CR85颗粒料在渣面层被侵蚀,主要是渣中的FeO和Al2O3对颗粒料的侵蚀,FeO与骨料中的Cr2O3反应,首先形成(Fe,Cr)3O4尖晶石,再与其他物相反应形成了复合尖晶石,当FeO耗尽后,渗入到颗粒内的Al2O3开始和Cr2O3反应,在颗粒表面形成铝铬固溶体;CR60颗粒料在渣面层和渗透层都存在侵蚀,渗透层的侵蚀主要是CaO、SiO2对颗粒料中铝铬固溶体中Al2O3的熔蚀,形成钙长石、钙黄长石以及玻璃相;Cr2O3含量较低的CR50、CR40、CR15颗粒料在渗透层内的侵蚀机制和CR60颗粒料的相同。