Temperature dependence of the viscosity for some glasses in the Rb2O-B2O3-SiO2 system

The temperature dependences of the shear viscosity of glasses in the Rb₂O-B₂O₃-SiO₂ system are investigated using the bending method on a quartz viscosimeter in the viscosity range 10¹¹-10¹³ P.     

Phase equilibria and thermodynamic properties of components in the Cs2O-B2O3-SiO2 system at high temperatures

The phase equilibria in the Cs₂O-B₂O₃-SiO₂ system are investigated in the temperature range 873–1073 K by the annealing-quenching technique, high-temperature microscopy, and X-ray powder diffraction analysis. The vapor composition, the activities of the components, and the Gibbs energies of glasses and melts in the Cs₂O-B₂O₃-SiO₂ system are determined at a temperature of 1020 K. It is demonstrated that glasses and melts in the Cs₂O · B₂O₃-Cs₂O · SiO₂ system are characterized by positive deviations of the CsBO₂ activities and negative deviations of the Cs₂O · SiO₂ activities from ideal behavior. As a consequence, the deviations of the Gibbs energies from ideal behavior change their sign.     

Calculations of the thermodynamic properties of glasses and melts in the Cs2O-B2O3-SiO2 system in the framework of the generalized lattice theory of associated solutions

The possibility of calculating the thermodynamic properties of glasses and melts in the Cs₂O-B₂O₃-SiO₂ system formed by two glass-former oxides and one modifier oxide with the use of the vacancy variant of the generalized lattice theory of associated solutions is demonstrated. A comparison with the experimental thermodynamic functions determined earlier by high-temperature differential mass spectrometry and electromotive force method shows that the calculations performed within this approach lead to reliable thermodynamic functions. The thermodynamic properties and structural features (the relative numbers of bonds with due regard for the second coordination sphere) of glasses and melts in the Cs₂O-B₂O₃-SiO₂ system are analyzed in terms of the generalized lattice theory of associated solutions.     

Mass spectrometric investigation of the thermodynamic properties of glass melts in the Cs2O-B2O3-SiO2 system at high temperatures

The composition of the vapor and the activities of cesium metaborate CsBO₂ in glass melts of the Cs₂O-B₂O₃-SiO₂ system at a temperature of 1020 K are determined using high-temperature mass spectrometry. The activities of the individual oxides Cs₂O, B₂O₃, and SiO₂ in glass melts of the Cs₂O-B₂O₃-SiO₂ system at a temperature of 1020 K are calculated by the Wagner method from the obtained values of the activities of CsBO₂. The integral and excess Gibbs energies are determined.     

Metastable Immiscibility Surface in the System Na2O-B2O3-SiO2*

Opalescence and clearing techniques were used to determine the metastable immiscibility surface for sodium borosilicate solutions. These results indicate that a three-liquid region, which may or may not be metastable to two-liquid regions, underlies the immiscibility surface.     

Simulation of the thermodynamic properties of glass melts in the Cs2O-B2O3-SiO2 system in the concentration range 0.06–0.50 mole fractions of Cs2O at a temperature of 1020 K

The possibility of calculating the thermodynamic properties of glass melts in the Cs₂O-B₂O₃-SiO₂ system with the use of the vacancy variant of the generalized lattice theory of associated solutions is demonstrated. A comparison with the experimental thermodynamic functions previously determined by high-temperature mass spectrometry shows that the calculations performed within this approach lead to reliable thermodynamic functions for glass melts in the Cs₂O-B₂O₃-SiO₂ 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     

Li_2O-Na_2O-B_2O_3-SiO_2系无铅低温透明熔块的研制

探索用Li2O-Na2O-B2O3-SiO2新的配方系统配制无铅低温透明熔块的方法。制得使用温度为740~780℃的低温无铅透明熔块,以熔块配制成的低温透明熔块釉可作为生产陶瓷装饰色料中的低温熔剂。     

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.     

Structure and electrical conductivity of Li2O-B2O3 glasses

The temperature-concentration dependence of the electrical conductivity of Li₂O-B₂O₃ glasses in the temperature range of ～180–310°C has been studied. For pure boron anhydride, the dependence logσ = f([1/T]) is linear, whereas for glasses with ～2 mol % ≤ [Li₂O] < ～10 mol %, similar curves are kinked. At higher Li₂O concentration the kinks disappear. Occurrence of kinks is attributed to variation of essence of current carriers from proton pattern for B₂O₃ to mixed proton-ion pattern for low-alkali glasses. Conductivity of glasses at [Li₂O] ≥ 20 mol % is stipulated by the formation of a continuous sublattice of polar structuralchemical entities (entities) [BO_4/2]^?Li⁺ and the migration of lithium ions.     

Criterion for estimating the number of phases in phase-separated glass of the Na2O-K2O-B2O3-SiO2 system by dilatometric analysis

The data of dilatometry and electron microscopy of four series of xNa₂O-(8 ? x)K₂O-32B₂O₃-60SiO₂, xNa₂O-(8 ? x)K₂O-22B₂O₃-70SiO₂, xNa₂O-(6 ? x)K₂O-34B₂O₃-60SiO₂, and xNa₂O-xK₂O-(40 ? 2x)B₂O₃-60SiO₂ phase-separated glass heat-treated at 550°C for 144 h (for glass containing 70 mol % SiO₂) and 24 h (for glass containing 60 mol % SiO₂) for separation on phases are summarized. The comparison of dilatometric data and electron microscopy allow one to conclude that glass with a difference between the onset deformation temperature and a glass transition temperature of more than 100°C is phase-separated; and glass with a difference of less than 65°C is single-phase. Curves for the glass transition temperature as a function of the K₂O content reveal a mixed alkali effect, namely, minimums for glass containing 60% SiO₂, and maximums for glass containing 70% SiO₂.     

The nature of charge carriers and their transport numbers in glasses of the Ag2O-B2O3 system

The temperature-concentration dependence of the dc electrical conductivity of glasses in the xAg₂O-(1 ? x)B₂O₃ (0.05 ≤ x ≤ 0.25) system is investigated using active (amalgam) electrodes. A series of glasses are synthesized with the use of D₂O as an isotope tracer. The analysis of data on the electrolysis of glasses at 0.15 ≤ x ≤ 0.225 demonstrates that charge carriers in these glasses involve protons formed upon dissociation of impurity water. The water content is evaluated by IR spectroscopy. The electronic component of the total electrical conductivity is determined by the Liang-Wagner technique. It is shown that the contribution of the electronic component does not exceed the sensitivity of the technique (10^?2—10^?3%). The participation of silver ions in electricity transport processes is studied by the Hittorf method. It is demonstrated that their transport numbers do not exceed 0.53. A comparison of the physicochemical properties of glasses in the Ag₂O-B₂O₃ and Na₂O-B₂O₃ systems shows that sodium and silver ions occupy different positions in the structure.     

Structure of low-silica glasses in the K2O-Nb2O5-SiO2 system

The nanostructure and nonlinear optical properties of high-niobium glasses in the (1 ? x)KNbO₃-xSiO₂ system with an SiO₂ content x = 0.05–0.35 have been studied by small-angle neutron scattering (SANS), electron microscopy (EM), and second-optical-harmonic generation (SHG). Vitreous samples are manufactured by the methods of fast melt cooling (pressing with metal plates and quenching between rotating rolls). Glasses with x < 0.12 have been established to form a micro-inhomogeneous structure in the form of silica-enriched regions at the cooling rates used. According to SANS data, quenched glasses with x > 0.2 are homogeneous, but form a silica-enriched nanostructure after thermal treatments. At temperatures below ～T _g + 50°C, silica-enriched regions manifest a very slight tendency to grow, whereas, according to SANS and X-ray diffraction data, their chemical composition is observed to shift appreciably towards SiO₂ with thermal treatment. The obtained data on an inhomogeneous structure allows us to clarify the complicated character of the previously revealed dependence T _g (x). Nano-inhomogeneous transparent samples produce a weak SHG signal, which indicates the quasi-periodic modulation of the chemical composition and, correspondingly, polarizability, in the volume of glass. The nonlinear optical phase KNbO₃ precipitates at later stages of crystallization, when a glass loses its transparency. In this case, the SHG signal is amplified by several orders of magnitude.     

金刚石增强Na2O-B2O3-Al2O3-SiO2系陶瓷基复合材料的界面研究

以Na2 O-B2 O3-Al2 O3-SiO2系低温玻璃为基础结合剂烧制金刚石增强陶瓷基复合材料,利用扫描电子显微镜、X射线能谱、X射线光电子能谱、拉曼光谱及力学性能测试仪等对其界面结合强度、界面处元素分布及界面化学键进行了表征.结果表明,Na2 O-B2 O3-Al2 O3-SiO2系陶瓷结合剂与金刚石颗粒界面结合...     

Na2O-B2O3-SiO2-TiO2玻璃分相与析晶的研究

熔融分相法是制备负载型纳米TiO2光催化材料的新方法。该方法是以Na2O-B2O3-SiO2-TiO2系为研究对象,通过制备不同组成的样品,并进行X射线分析及显微分析,进一步研究了熔融分相法中玻璃分相与TiO2析晶的关系。结果表明:组成在玻璃分相区域的样品,有玻璃分相现象产生,TiO2晶体能够析出,而在未分相区域的组成,样品中没有产生玻璃分相,TiO2晶体不能析出;玻璃分相的结构影响了TiO2晶体的生长,相同热处理条件下,组成中硅含量越少,其玻璃分相程度越大,TiO2析晶越容易,TiO2的析晶尺寸越大。     

含PbS微晶掺杂Na2O-B2O3-SiO2玻璃的制备及其光学性质

采用溶胶－凝胶方法合成了含有硫化铅的钠硼硅干胶,通过与硫化氮气体反再进行密实化处理,成功地制备了含有硫化铅微晶的钠硼硅系统玻璃。     

Tm3+-Yb3+双掺Li2O-B2O3-SiO2系透明玻璃陶瓷的制备及表征

本文制备了以Li2SiO3为主晶相Li2O-B2O3-SiO2系透明玻璃陶瓷,并研究了B2O3的含量对于玻璃陶瓷结构的影响.利用DSC、XRD和SEM等测试手段进行了表征.以Tm3+/Yb3+共掺作为上转换研究对象,研究了该系玻璃陶瓷的光谱性质.在980 nm激光激发下,Tm3+/Yb3共掺的LBS系玻璃陶瓷中观察到强的474 nm的蓝色、650nm的红色上转换发光,并确定蓝红光均为三光子过程.研究了上转换发光与Tm3+/Yb3+质量比的关系.     

Structure of Cs2O-B2O3 glass and melts: The Raman spectroscopy data

The study continues a series of works of the authors dedicated to the investigation of the alkaliborate glass and melts, in order to determine the structure of samples of the xCs₂O-(100 ? x)B₂O₃ (x ≤ 40 mol %) composition in glassy, supercool, and molten conditions with the high-temperature Raman spectroscopy. The Raman spectra were analyzed to identify the type of structural units in glass and melts and the variation in structure depending on composition and temperature.