Bi2O3/ZnO比例对真空玻璃用低熔点封接玻璃结构和性能的影响

制备了可用于真空玻璃封接的铋酸盐玻璃系统无铅低熔点玻璃粉,采用拉曼光谱、XRD、热膨胀测试、纽扣实验等测试方法表征了Bi2O3/ZnO比例的变化对玻璃的网络结构、热学性能、热膨胀系数、特征温度点及封接温度的影响.结果 表明:随着Bi2O3/ZnO比例的增加,[BiO3]和[BiO6]单元数量随之增多,少部分Zn2+以[ZnO4]四面体结构进入到玻璃网络结构中.Bi2O3/ZnO比例的增加,降低了玻璃的Tt、Ts和封接温度,增大了热膨胀系数,增强了化学稳定性.Bi2O3/ZnO最佳比例是35/26.7,此时玻璃具有较低的Tg(384℃)和Ts(407℃),热膨胀系数为98.6×10-7/℃,封接温度为(456±14)℃.本实验的Bi2O3用量少,封接温度低,无须添加低膨胀填料即可获得较低的热膨胀系数,降低了生产成本,满足真空玻璃对低熔点封接玻璃粉的使用要求.     

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。     

CuO对ZnO-Bi2O3-B2O3系玻璃结构及热处理结果影响

本研究以ZnO-Bi2O3-B2O3系为基础,采用熔融-淬冷法制备玻璃,用FT-IR、DTA、DIL(膨胀仪)和XRD以及测量样品收缩率等,研究了添加CuO对该玻璃的结构、转变温度(Tg)、析晶情况、烧结及流散性的影响.FT-IR分析表明,随着玻璃中CuO含量增加,与[ZnO4]和[BiO6]结构有关的峰由517移到523 cm-1;但没有改变玻璃中[BO3]结构多于[BO4]的基本情况.DTA分析表明,该基础玻璃的Tg为447℃,第一结晶温度(Tc1)为604℃,第二结晶温度(Tc2)为820℃;添加0.5 wt.%CuO后,T和Tc2不变,Tc1降至523℃;XRD分析也发现添加CuO玻璃在530℃出现了较明显衍射峰.添加少量CuO,有助于玻璃致密化,使玻璃产生流散的温度降低,从而有利于封接.     

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.     

ZnO对ZnO-B2O3-SiO2低熔点玻璃结构与性能的影响

ZnO-B2O3-SiO2玻璃是一类重要的低熔点玻璃,在玻璃深加工领域具有重要的应用.在ZnO-B2O3-SiO2玻璃中,ZnO含量的变化对玻璃结构和性能产生显著的影响.因此,本文调整ZnO-B2O3-SiO2玻璃中ZnO的引入量,结合DSC、红外光谱等测试手段,研究ZnO对玻璃的网络结构、热学性能、化学稳定性的影响规律.研究结果表明:随着ZnO含量的增多,Zn2+以[ZnO4]四面体结构进入到玻璃网络体结构,出现了[BO4]结构体向[BO3]结构体的转变.ZnO含量的增加,降低了玻璃的Tg和Ts,增大热膨胀系数,增强化学稳定性.ZnO的最佳引入量是32%,此时玻璃具有较低的Tg(495 ℃)和Ts(529 ℃),热膨胀系数为8.96×10-6 /K ,耐酸碱性能等级均为A级.在ZnO-B2O3-SiO2玻璃涂覆应用中,最佳的烧结温度为560 ℃,在ZnO含量为 32%时,涂覆层硬度最佳,硬度值为648.9 Hv.     

P2O5-B2O3-V2O5无铅低熔玻璃形成能力和结构

以取代用作封接玻璃和电子浆料粘接相含铅低熔玻璃为目的,实验研究了P2O5-B2O3-V2O5体系玻璃的形成能力,结构和低熔性能.P2O5-B2O3-V2O5体系中,组成在B2O35%～30%、V2O50%～45%、P2O35%～50%(物质的量浓度,下同)区域内的玻璃具有较强的玻璃形成能力,较低的转变温度、良好的重熔流动性和抗析晶性能.优选玻璃组成为:15P2O5-35V2O5-25B2O3-3SiO2-2Al2O3-10ZnO-5SnO-7BaO-3Bi2O3,玻璃转变温度为308℃,在450℃玻璃细粉重熔熔体流动性好,适合用作在450～500℃烧结的封接玻璃和电子浆料的粘接相.红外光谱分析表明:玻璃结构是由大量孤立的[PO4]、[BO3]、[VO2]和[VO3]基团形成的层状结构,在层与层之间有少量的诸如B-O-B、P-O-P、P-O-V、P-O-B等桥氧键连接.     

BaO含量对ZnO-B2O3-Bi2O3-BaO系玻璃结构及性能的影响

采用熔融法制备了ZnO-B_2O_3-Bi_2O_3-BaO系玻璃,利用傅里叶红外光谱仪(FT-IR)、拉曼光谱(Raman)、X射线衍射(XRD)、扫描电子显微镜(SEM)、差示扫描量热法(DSC)和热膨胀仪等技术手段研究了不同BaO含量(摩尔分数)(0~20%)对该体系玻璃结构及热性能的影响,采用质量损失法评价了玻璃的耐水性。结果表明:在所研究组成范围内,熔制温度为880℃均可制得均质玻璃;随着BaO含量的增加,玻璃特征温度呈上升趋势,玻璃的热稳定性逐渐增强,[BO_4]四面体逐渐转化为[BO_3]三角体,[BiO_6]八面体转化为[BiO_3]三角体,玻璃密度减小,耐水性变差,热膨胀系数增大。     

Bi_2O_3-B_2O_3-WO_3系统微晶玻璃的制备

采用熔融法制备了0.97[x Bi2O3(1-x)B2O3]·0.03WO3(0.25≤x≤O.75)基础玻璃,通过差热分析确定玻璃的特征温度,经热处理制备微晶玻璃.结果表明所制备的玻璃中只有x =0.67和x=0.60两个组成经热处理生成了微晶玻璃,颜色为乳黄色,晶相分别为BiO2和Bi2WO6,在扫描电镜下观察两种晶体的形貌均为颗粒状,晶粒尺寸在0.8～1.0μm.该体系玻璃的密度较大而硬度较小,但热处理后的微晶玻璃的密度和硬度均大于处理前的基础玻璃.     

Bi_2O_3–ZnO–B_2O_3三元系统玻璃结构与性能

采用X射线吸收精细结构和红外吸收光谱分别对铋锌硼玻璃中铋离子邻近结构和硼氧网络结构进行研究,分析其结构变化对玻璃转变温度Tg和热膨胀系数α的影响。结果表明:1)铋离子以三配位([BiO3])和六配位([BiO6])两种配位状态存在;随Bi2O3含量增加,三配位铋离子的配位数上升,六配位铋离子配位数下降,同时铋离子总配位数上升。2)随Bi2O3含量增加,硼氧网络中硼氧四面体含量下降,硼氧三角体含量上升,硼氧四面体网络解聚形成硼氧三角体网络。3)上述结构因素是造成玻璃转变温度Tg下降和热膨胀系数α上升的主要原因。     

含Y2O3的ZnO-Bi2O3-B2O3系统玻璃热学与电学性能研究

用红外光谱仪、拉曼光谱仪和差热分析仪研究了用“熔化-急冷”制得的用于SOFC封装的含Y2O3的ZnO-Bi2O3-B2O3系统玻璃的结构和转变温度(Tg);用X射线衍射仪、热膨胀系数仪和高阻计研究了由“模压成型-热处理”制得的该玻璃制品的微晶化、热膨胀系数(α)和体积电阻率(p)情况.结果表明:Y2O3≤0.5～1.0wt.％时,Y2O3能促进[BO3]向[BO4]转变,使α降低;Y2O3≥0.5～1.0wt.％时,玻璃中Bi-O键增多,又使α降低趋势趋缓;随Y2O3增加,其作用可能由破坏网络结构逐渐向增强网络结构转变,致T8先降后升;添加Y2O3延缓了玻璃的析晶;微晶化能提高α和ρ;添加Y2O3虽致α和ρ下降,但其值仍在SOFC封接玻璃的要求范围内.     

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。