Electrode Properties of Fluorine-Containing Alkali Silicate Glasses

An attempt is made to change the electrode properties of alkali silicate glasses containing various glass-formers and modifiers by introducing fluorine components into their compositions. Model systems with the initial hydrogen and metallic electrode functions are investigated. The study is based on the assumption that new ionogenic structural units with a mixed-anion constituent are formed in the glass structure. Lithium, sodium, and potassium silicate glasses with different fluorine contents are synthesized. Their potentiometric properties are studied. It is shown that the introduction of fluorine exerts the strongest effect on the electrode properties of alkali aluminosilicate glasses. An indirect corroboration is obtained for the assumption that strongly acid groupings containing fluorine can be formed in the glass network. It is found that the technological properties of the electrode glasses are significantly improved and the chemical durability in the potassium-containing system also becomes much higher. From the results obtained, the inference is drawn about the prospects of fluorine introduction into electrode glasses.     

Predicted Mechanism for Enhanced Durability of Zinc Containing Silicate Glasses

Experimental studies have reported that zinc oxide improves the durability of glasses used for nuclear waste immobilization. Here, molecular dynamics simulations are used to predict the atomic structures of sodium silicate glass with and without zinc. A simulated melt‐quench procedure is used to generate glass structures. Pair distribution functions, ring size distributions, and alkali clustering are then examined. This allows insights into the structural role of zinc oxide within the glass and helps distinguish between its reported functions as a network former and a network modifier. Changes in the sodium ion distribution and clustering behavior within the glass are observed, due to zinc oxide addition. This affects the local and intermediate‐range structure of the glass and provides a possible explanation for enhanced durability.     

锂铝硅玻璃的研究进展

与传统的钠钙硅玻璃和高铝玻璃相比,锂铝硅玻璃具有网络结构致密、弹性模量较高和适宜两步法化学钢化等特点,被视为第三代高强玻璃基板,可用作电子信息产品盖板、航空透明器件以及舰船、特种车辆的观察窗口等。目前,锂铝硅玻璃的研究主要涉及:(1)探究锂铝硅玻璃的“组成-结构-性能”本构关系,为设计优化高性能锂铝硅玻璃提供理论指导和性能预测;(2)改进现有溢流和浮法成型方法和装备,满足大尺寸、多厚度和高尺寸精度锂铝硅玻璃成型需要;(3)研究锂铝硅玻璃的两步法化学增强方法,解决表面压应力和应力层深度同步提升难题,显著提高玻璃强度、硬度和抗跌落性能。本文基于上述三个方面综述了锂铝硅玻璃的国内外研究进展。     

Property/Morphology Relations in Alkali Silicate Glasses

The effects of glass composition and thermal history on the glass-transformation range behavior, as indicated by thermal expansion curves, and on chemical durability, as indicated by the acid etch rate, were measured for binary lithium, sodium, and potassium silicate glasses and for the lithinm/sodium and lithiumlpotassium mixed-alkali silicate glasses. The results were used to determine the phase-separation boundaries and the limits of interconnectivity of each phase for all five systems. The results demonstrate the utility of such studies for the characterization of the morphology of glass-forming systems.     

Sulphur-polypyrrole composite positive electrode materials for rechargeable lithium batteries

A novel conducting sulphur-polypyrrole composite material was prepared by the chemical polymerization method with sodium p-toluenesulphonate as the dopant, 4-styrenesulphonic sodium salts as the surfactant, and FeCl₃ as the oxidant. The new material was characterized by Raman spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Nanosize polypyrrole particles were uniformly coated onto the surface of the sulphur powder, which significantly improved the electrical conductivity, the capacity and the cycle durability in a lithium cell compared with the bare sulphur electrode.     

玻璃中离子注入研究的现状与发展趋势

早期的论文报道了离子注入对机械性能的改性是由于离子碰撞和辐照损伤的结果，近期工作指出注入离子与玻璃基片相互作用，造成结构变化，化合物形成，分相，纳米粒子的聚集，所以离子注入影响玻璃的风化，化学稳定性，非线性光学，电导率和晶体，离子注入引起玻璃性能改变，取决于玻璃成分，注入离子种类，注入参数（能量和剂量）以及热处理制度，离子注入已应用于改善玻璃显微硬度，风化能力，耐水性和晶体形貌，在不影响玻璃其他性能条件下，用离子注入可以提高磷酸盐光学玻璃的化学稳定性，降低电极玻璃电阻率，金属离子注入玻璃导致玻璃基片表面纳米簇的形成，这些纳米粒子呈现的等离子体激元震荡导致玻璃的非线性光学性质增强，因此离子注入的玻璃可以应用于全光学开关器件，本文还指出了离子注入今后研究的方向和应用前景。     

Studies of sintering of coal ash relevant to pulverized coal utility boilers: 1. Examination of the Raask shrinkage—electrical resistance method

The Raask shrinkage and electrical resistance method for determining the onset of sintering of fly ash has been tested on a soda lime glass, coal ASTM ashes, fly ashes and pulverized synthetic mineral mixtures. Results with the glass confirmed those of Raask and showed that particle size distribution and bulk density affected the resistance values: the sinter point was indicated by a change in the characteristic temperature coefficient of resistance. The shrinkage and electrical sinter points were usually the same, but a high Na content lignite gave 850°C for shrinkage but 600°C for characteristic resistance change. Sinter points were 200°C less for fly ash than for ASTM ash. The fly ashes had a slight enrichment of alkalies and a decrease in Fe content compared to the total ash. Holding a compact at a temperature above the sinter point gave increased strength and shrinkage, but no decrease in electrical resistance, indicating that the decrease in resistance as temperature increased was due to the establishment of contact points between particles, with little effect of the continued growth of a contact neck. Addition of pulverized sodium silicate or iron silicate glasses to a synthetic ash also reduced the sinter points, as did alkali additions, whereas addition of pyrite did not. It was concluded that the method was a valuable tool, but sources of variability had to be determined and controlled.     

Ion Depletion of Glass at a Blocking Anode: I, Theory and Experimental Results for Alkali Silicate Glasses

A theory is presented for the ion depletion of glass beneath a blocking anode. The theoretical model is based on the assumption that the alkali ions in an alkali silicate glass have a much greater mobility than the nonbridging oxygen ions in the alkali-depleted region. In this case, the dc conduction properties of the glass are determined by the motion of the uncombined oxygen ions in the depleted region. Expressions are derived for the spatial variation of the uncombined oxygen ions and for the current-voltage relations in the high- and low-field limits. In the high-field limit, the theory predicts that the current will vary exponentially with the voltage; this behavior is shown in sodium silicate glasses.     

Anelasticity of Glass: III, Effect of Heat-Treatment on the Internal Friction of Tank Plate Glass

Heat-treatment or annealing decreases the internal-friction peak commonly attributed to sodium ion diffusion in tank plate glass, a typical soda-lime-silica glass. The peak is shifted to higher temperatures at constant frequency of vibration or to lower frequencies at constant temperature. The activation energy for the shift is greater in the annealed glass and agrees with the activation energy for the electrical conductivity and alkali durability of annealed glass. Heat-treatment also decreases the internal friction caused by elastico-viscous effects.     

四硼酸钠改性水玻璃制备保温材料及其性能研究

单一水玻璃发泡制备得到的保温材料具有不燃、质轻及导热系数低的优点,但耐水性较差制约了其实际应用。本文利用四硼酸钠改性水玻璃,采用低温烧结的方式制备得到保温材料。通过对该材料化学结构和物理性能的表征及离子浸出试验,研究四硼酸钠对材料性能的影响效果。结果表明:四硼酸钠能够有效降低材料中—OH的数量,并使Si—O结构更加复杂,从而提高材料的耐水性。当四硼酸钠的添加量为1%(质量分数,下同)时,其对材料中钠离子及硅酸根离子浸出的抑制效果最显著,两者的离子浓度分别降低65.33%和45.02%。当四硼酸钠的添加量为3%时,材料的软化系数可提高84.6%,其抗压强度、导热系数和表观密度分别为0.46 MPa、0.046 W/(m·K)和123.1 kg/m³。     

玻璃表面的FeCl3浸渍层在碱液中的稳定性

本文通过玻璃受碱侵蚀的失重，侵蚀液的原子吸收光谱分析，Ｘ射线光电子能谱分析，研究了ＦｅＣｌ３表面浸渍层在碱溶液中的稳定作用，玻璃在碱液中侵蚀时，Ａｌ２ｐ和Ｓｉ２ｐ电子结合能降低，这是因为ＯＨ＾－对玻璃表面的侵蚀引起了玻璃骨架中Ｓｉ－Ｏ－Ｓｉ和Ａｌ－Ｏ－Ａｌ键的断裂，表面生成了铝酸盐和硅酸盐凝胶。ＦｅＣｌ３对玻璃表面的浸渍作用割断了碱对玻璃表面的直接作用，因而具有抗碱侵蚀能力。     

Anti-acid corrosion mechanism of yttrium oxide doped barium borosilicate glass

Designing glass with excellent acid resistance is a prerequisite for developing high-performance terminal electrode pastes. Herein, we fabricated Y₂O₃ doped BaO–B₂O₃–SiO₂ glass with excellent anti-sulfuric acid corrosion properties. The anti-corrosion mechanism of glass in acid environment was investigated by spectra and microstructure analysis. The passivating gel layer with a porous structure was formed on the glass surface during the corrosion process. The average pore diameter of the porous gel could be reduced by increasing the content of Y₂O₃. The smaller pore size of the porous gel would considerably increase the collision frequency between solvent molecules and the pore wall, which could effectively inhibit the ion migration in the gel layer, reduce the corrosion rate, and improve the acid resistance of the glass. This study contributes to the understanding of the corrosion mechanism of the glass and provides theoretical guidance for rationally designing anti-acid corrosion glass for terminal electrode pastes.     

氟锆酸盐玻璃的混碱效应

４８Ｚｒｆ４－２４ＢａＦ２－８ＡｌＦ３－２０ＲＦ（ＲＦ＝ＬｉＦ－ＮａＦ和ＮａＦ－ＫＦ）玻璃中引入不同比例的碱金属离子。利用ＤＴＡ研究玻璃的成玻性，并测定玻璃的化学稳定性和折射率。讨论了各理化性能的混碱效应。结果表明，混碱氟锆酸盐玻璃的成玻性和化学稳定性均优于单碱玻璃。当ＲＦ为ＬｉＦ－ＮａＦ且ＬｉＦ：ＮａＦ为１：３时有最佳的成玻能力，ＬｉＦ：ＮａＦ为１：１时玻璃有最好的化学稳定性。     

Correlation between the gel layer properties and the electrochemical behaviour of hydrogen selective glass electrodes

Some pH-responsive glass electrodes have been characterised with respect to gel layer thickness, durability and ion exchange capacity. Glasses with a low durability exhibited a thick gel layer and a high ion exchange capacity in comparison with high durability glasses. The electrochemical properties were judged by measuring the asymmetry potential, the acid and alkaline errors and the kinetic pattern obtained in going from base to acid. It was concluded that the thinner the gel layer the more ideal the electrode function. The results indicate that the gel layer properties rather than the bulk glass properties should be considered in predicting the electrochemical behaviour.     

Anelasticity of Glass: II, Internal Friction and Sodium Ion Diffusion in Tank Plate Glass, A Typical Soda-Lime-Silica Glass

The internal-friction peak observed near room temperature in tank plate glass at a period of the order of seconds and previously attributed to sodium ion diffusion is further discussed. The temperature of maximum internal friction is shown to vary with the frequency of vibration with an activation energy of about 16 kg.-cal. Per mole for air-chilled glass fibers. Likewise, the activation energy for the electrical resistivity of the chilled glass is about 16 kg.-cal. Although the activation energy for sodium ion diffusion and alkali durability is about 21 kg.-cal., it too can be properly interpreted to confirm that the internal friction peak is caused by sodium ion diffusion. The internal friction peak is much broader than can be accounted for by a single relaxation mechanism. However, a dispersion of relaxation mechanisms is consistent with the accepted theory of randomness in the silica network.     

Alkali Durability of Oxynitride Glass Fibers

Oxynitride glass fibers were drawn from the melt in N₂ atmospheres. The fibers were tested for their alkali durability in 10% NaOH at 96°C for 6 h. The durability is reported as weight loss in mg/cm². The photomicrographs of the fibers before and after testing are presented. Calcium silicate oxynitride fibers have good durability because of a protective surface layer of Ca(OH)₂. Yttria-containing glasses have the best durability among the compositions reported here.     

离子交换增强玻璃表面化学稳定性的研究

系统研究了化学钢化及盐溶液后处理对Na2O-CaO-SiO2玻璃表面化学稳定性的影响。详细考察了用熔融KNO3化学钢化的玻璃以及用适当盐溶液后处理的化学钢化玻璃,在受水侵蚀后R2O的沥滤量和失重以及受碱侵蚀后SiO2的溶出量和失重。结果表明,用熔融KNO3对玻璃进行钢化处理后,玻璃的耐水性和耐碱性均有明显下降。而将化学钢化的玻璃利用适当盐溶液处理后,可以改善钢化玻璃的化学稳定性,因而可以进一步提高化学钢化玻璃的使用性能和拓展其使用范围。     

Ion Depletion of Glass at a Blocking Anode: II, Properties of Ion-Depleted Glasses

The application of an electric field to an ion-conducting glass at high temperatures will cause depletion of mobile ions beneath a blocking anode. The present study extends the investigation of ion depletion to several types of ion-conducting glass and presents new data for the physical and chemical properties of depleted surfaces. Ion-scattering spectrometry and electron microprobe analysis show that all positive monovalent and divalent ions are removed from the vicinity of the anode. The less mobile ion species are observed to pile up beneath the depleted region. Experimental data indicate that the removal of ions from the vicinity of the anode creates a microporous region that densifies at a rate determined by glass composition, temperature, and voltage. Ion-depleted surfaces display a lower refractive index and an increased electrical resistivity compared to untreated glass. Ion depletion also imparts an enhanced chemical durability to glass surfaces and increases the breaking strength of some glasses.     

玻璃纤维碱侵蚀机理和耐碱性的探讨

介绍了GRC发展背景,讨论了碱侵蚀机理、化学和物理腐蚀机理及GRC性能和耐久性。通过对玻璃纤维碱侵蚀机理和耐碱性的探讨,得出了水泥基对玻璃纤维的腐蚀作用包括氢氧离子和硅氧四面体的化学作用和静态疲劳过程的物理作用及玻璃纤维因成分和结构的不同有很大的差异等结论。     

熔铸耐火材料抗盖板玻璃熔体侵蚀行为研究

本文以熔铸耐火材料为研究对象进行抗盖板玻璃熔体侵蚀试验,采用化学分析、岩相分析和电子显微镜能谱分析等测试分析方法,对比研究钠钙玻璃熔体、高铝玻璃熔体和锂铝玻璃熔体对熔铸耐火材料的侵蚀行为。结果表明,玻璃熔体中的碱金属离子向耐火材料中的玻璃相扩散,导致玻璃相黏度降低,同时耐火材料中刚玉相溶解,斜锆石分散,主体结构遭到破坏,并形成界面层。界面层内存在富铝含锆的玻璃相,由于高铝玻璃和锂铝玻璃氧化铝含量高,表面张力大,界面层内的玻璃相聚集在试样周围且扩散慢,从而阻止了侵蚀的发展。玻璃熔体的侵蚀速率为钠钙玻璃熔体＞高铝玻璃熔体＞锂铝玻璃熔体。