Residual Stress Analysis of Commercial Float Glass Using Digital Photoelasticity

Residual stresses are generated in float glass at the time of manufacturing due to thermal gradients created during the cooling process. The quantification of these residual stresses is important in glass industries as they affect their cutting quality. Photoelasticity can be used for residual stress analysis of glasses, as glass exhibits stress-induced birefringence. In this study, a methodology involving carrier fringes in conjunction with digital photoelasticity is used to quantify the residual stress in float glass. The results are verified by six-step phase-shifting technique (a subset of ten-step phase-shifting method) using an automatic polariscope. Finally, to demonstrate the utility of the proposed method, the residual stress is measured in float glasses of different thicknesses. A method for approximate estimation of residual stress which does not require sophisticated digital image acquisition and processing systems is also reported.     

Recycling of waste glasses into partially crystallized glass foams

Waste soda-lime glass, alone or mixed with wastes from the manufacturing of glass fibers, was successfully converted into partially crystallized glass foams by a particularly simple and economic processing, consisting of a direct heating of glass powders at temperatures from 900 to 1050 °C. The foaming operated by the oxidation of SiC, inserted as powder additive, was found to depend on a complex combination of processing temperature, soaking time, tendency of the investigated glasses toward devitrification, and amount of MnO₂, acting as oxidation promoter. Selected combinations led to foams with a good microstructural homogeneity and mechanical strength, suitable for application as aggregates in lightweight concrete.     

Optimization of the synthesis route of a barium boron aluminosilicate sealing glass for SOFC applications

A barium boron aluminosilicate sealing glass for IT-SOFC or SOFC applications was synthesized using different routes. Notably, sol-gel and solid state processes were used in order to obtain homogeneous glasses at 1100–1300 °C. Sol-gel processes consist in a soft chemistry route allowing a better homogeneity between cationic precursors in the mixture and a better reactivity of the material. The influence of the process and of the glass processing temperature on the thermo-mechanical properties of the glasses were investigated after different heat treatments in air atmosphere, i.e. glass processing, sealing (850 °C-2 h) and ageing (800 °C-100 h) procedures. It had been observed that the grain size of the glass powder (obtained after the glass processing and used for the sealing operation) is determining in order to manage the sealing procedure. Some large pores were formed during the devitrification step of the glass made by solid state route while glass sealants synthesized by the sol-gel route even at 1100 °C remained suitable for SOFC applications after thermal treatments, which proved that the sol-gel process is useful to decrease the glass processing temperature.     

硅酸盐玻璃无规则网络理论的辩证法思考及教学方法浅析

无规则网络理论是硅酸盐玻璃最重要的基础理论之一。玻璃科学课程以形象的网络的概念对石英玻璃及其他硅酸盐玻璃的结构进行描述,并在此基础上对玻璃的性能进行分析。本文利用辩证法的三大规律——对立统一规律、量变质变规律和否定之否定规律对石英玻璃的无规则网络结构理论的辩证法内涵进行了探讨,并在此基础上,进行了硅酸盐玻璃结构的辩证法分析。在上述辩证法剖析的基础上,对玻璃无规则网络理论的教学方法提出了新的思考。     

A New Quick Test to Determine the Structure of Opacified Glasses

The structure of glass opacified with phosphor is investigated as a function of its thermal prehistory using the positron annihilation method, x-ray phase, and electron microscope analysis. Structural differences are identified, which depend on the wall thickness of articles and the temperature conditions of annealing. It is proposed to use this method for a quick test of the homogeneity and the degree of annealing of opaque glasses.     

Yb3+掺杂YAG微晶玻璃的制备与晶化性能研究

通过对CaO-Al2O3-SiO2三元相图相关点的探讨,确定Yb3+掺杂的29.5SiO2-30.5CaO-24 Al2O3-12Y2O3-4 Yb2O3-(0～3)ZrO2玻璃系统,采取高温熔融获得母体玻璃。用DTA和梯温法测定母体玻璃的析晶行为并确定热处理制度。采取XRD,TEM分析热处理后的样品。结果表明,选择的玻璃成分均可得到Yb3+掺杂YAG透明微晶玻璃,含3 mol%ZrO2更有利于得到晶体颗粒的形貌和大小基本一致、分散均匀、尺寸约33 nm的Yb3+掺杂YAG透明微晶玻璃。     

Silicon oxycarbide glasses and glass‐ceramics: “All‐Rounder” materials for advanced structural and functional applications

Silicon oxycarbides can be considered as being carbon‐containing silicates consisting of glass networks in which oxygen and carbon share bonds with silicon. The carbon‐for‐oxygen substitution in silicate glass networks has been shown to induce significant changes in the network connectivity and consequently strong improvements in the properties of the silicate glass network. For instance, SiOC glasses exhibit Young's moduli, hardness values, glass transition, and crystallization temperatures which are superior to those of vitreous silica. Moreover, the silicon oxycarbide glass network exhibits unique structural features such as reduced mass fractal dimension and nano‐heterogeneity, which significantly affect and/or dictate its properties and behavior. In the present Review, a consideration of the current state of the art concerning the synthesis, processing, and various structural and functional properties of silicon‐oxycarbide‐based glasses and glass‐ceramics is done. Thus, the synthesis of silicon oxycarbides starting from macromolecular precursors such as polysiloxanes or alkoxysilanes‐based sol‐gel systems as well as current advances related to their processing will be critically reviewed. In addition, various structural and functional properties of silicon oxycarbides are presented. Specific emphasis will be put on the intimate correlation between the molecular architecture of the precursors and the structural features and properties of the resulting silicon oxycarbides.     

Tailored waste based glasses as secondary raw materials for porcelain stoneware

Abstract

The high temperature processing of porcelain stoneware products is attractive for the possibility to incorporate several inorganic wastes. However, even if recycling is an environmental benefit, it can be disadvantageous for the overall properties of the ceramic product, if wastes are not selected in terms of their chemical and physical characteristics. In the present work several kind of industrial and urban wastes, such as mining residues, lime, glass from dismantled cathode ray tubes and soda lime glass were used, after their vitrification. These newly formed glasses were used as partial substitution for natural feldspar sands (the glass content being from 5 to 7 wt-% of the total mix). Owing to the specific ('tailored') chemical formulation of the newly formed glasses, the modified products exhibited higher crystallisation, with a more homogeneous microstructure, leading to significant improvements in reliability and indentation fracture toughness.     

Characterization on the yield stress and interfacial coefficient of friction of glasses from scratch tests

Based on dimensional analysis and finite element simulation, a new method is proposed to characterize the yield stress and interfacial coefficient of friction of materials by scratching with a Vickers indenter. Two simple equations are obtained: one is for determining the interfacial coefficient of friction between the scratched material and scratch tip via the ratio of tangential to normal force, and the other is for calculating the yield stress of scratched material with the groove width and normal force. In a case study, the method is applied to soda-lime and borosilicate glasses. It is shown that the measured results of yield stress and interfacial coefficient of friction between glasses and a diamond tip are consistent with that obtained by other methods, with a high accuracy. The quick and accurate determination of yield stress and interfacial friction coefficient provides important information for the design and processing of glass products.     

Elastic Moduli of Glasses at Elevated Temperatures by a Dynamic Method

The elastic constants of thirteen glasses were measured by a dynamic method at elevated temperatures. Both Young's modulus and the shear modulus were determined and from these Pois-son's ratio was calculated as a function of temperature. Fused silica, Vycor-brand glass, and Pyrex-brand glass had positive temperature coefficients of elastic moduli, whereas all the other glasses showed negative coefficients. Poisson's ratio was found to rise with temperature in all thirteen glasses. This is interpreted as an indication of an approach to the liquid state.     

Atomic and micro-structure features of nanoporous aluminosilicate glasses from reactive molecular dynamics simulations

Long-term chemical durability of borosilicate glasses that makes them a widely accepted form of nuclear waste disposal is achieved through the formation of a porous aluminosilicate gel layer that provides passivity and limits the transport of water to the reaction front. Detailed understanding of the porous silicate gel layer is thus critical in elucidating the corrosion mechanism of these glasses and to design of new glass composition for waste immobilization and other applications. In this paper, we use the diffuse charge reactive potential to generate porous aluminosilicate glass structures with compositions equivalent to the gel layers formed at the glass-water interface with an aim to understand the processing condition on the microstructure and atomic structure of these systems. We demonstrate the use of the charge scaling techniques is an effective approach to generate these porous structures with controllable pore mophologies. After initial validation of the potentials and calcium aluminosilicate glass structures using neutron diffraction, we created gel structures with compositions similar to well-known model nuclear waste borosilicate glasses. The porosities and the pore size distribution bear a strong correlation to the processing temperature, as well as to the local atomic structure. Thus, by controlling the processing parameters, the generated porous structures can be customized to closely resemble gel structures due to borosilicate glass corrosion. These results provide insights of the micro- and atomic structure features of the porous aluminosilicate glasses and on the optimal procedure to generate porous structures that can be comparable to experimentally observed gel layer structures thus to elaborate on the correlations between the structure and phenomena in glass-water interactions.     

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。     

STUDY OF PHOTOLUMINESCENCE IN GLASS*

The influence of composition and temperature on the fluorescence of glasses containing uranium and glasses containing cuprous oxide and stannous oxide was investigated. Secondary cations reduce the fluorescence of uranium in the glasses studied, depending to a certain extent on the electrostatic conditions they produce in the glass structure. The intensity of fluorescence as well as the structure of the spectrum diminishes in the order of phosphate, silicate, and borate glasses of equivalent compositions, which shows that fluorescence is favored by increase of oxygen in the glass structure without increasing the interfering secondary cations. Raising the temperature greatly diminishes the intensity of the fluorescence as well as the structure of the spectrum of glasses containing uranium. The fluorescence of the glasses containing cuprous oxide and stannous oxide as activators seems to be favored by increase in lime and increase in silica. These glasses possess appreciable phosphorescence, which appears to be enhanced by increase in silica and decrease in lime. A peculiar property of this type of luminescent glass is a maximum which it exhibits in its fluorescence-temperature relation-ship. There are indications that electrons are set free from the excited centers (copper atoms or small groups of copper atoms), which wander about in the glass structure.     

浅谈浮法玻璃断面条纹

玻璃均匀性是表征玻璃内在质量的一项重要指标,本文借助断面条纹图像,分析玻璃内在均匀性的好坏和形成原因,通过采取有效的工艺手段提高玻璃内在均匀性.     

Strength of Laminated Safety Glass for Construction Purposes

An analytical approach to determining the impact strength of laminated glass is considered. A method is proposed for reducing material and energy consumption and the production cost of multilayer glass through the use of glasses with induced surface stresses.     

Stress Corrosion and Static Fatigue of Glass

Stress corrosion cracking of six glasses was studied using fracture mechanics techniques. Crack velocities in water were measured as a function of applied stress intensity factor and temperature, and apparent activation energies for crack motion were obtained. Data were consistent with the universal fatigue curve for static fatigue of glass, which depended on glass composition. Of the glasses tested, silica glass was most resistant to static fatigue, followed by the low-alkali aluminosilicate and borosilicate glasses. Sodium was detrimental to stress corrosion resistance. The crack velocity data could be explained by the Charles and Hillig theory of stress corrosion. It is probable that stress corrosion of glass is normally caused and controlled by a chemical reaction between the glass and water.     

超薄铝硅玻璃离子交换工艺研究

高强度超薄盖板玻璃是电子信息产品的重要组成部分,化学强化(离子交换)是提升超薄盖板玻璃力学性能的主要技术途径。在离子交换过程中,玻璃易产生应力弛豫等现象,导致化学强化玻璃难以具备较高的表面压应力、较大的应力层深度与较高的维氏硬度。本文采用两步法离子交换工艺,研究了熔盐、离子交换温度与时间等因素对强化后超薄铝硅玻璃应力层分布及维氏硬度等性能的影响。结果表明,本文所研发的两步法离子交换工艺,可以使玻璃兼具较高的表面压应力、较大的应力层深度与较高的表面维氏硬度。离子交换后,铝硅玻璃的表面压应力可达900 MPa以上,应力层深度可达70 μm以上,同时表面维氏硬度达7.2 GPa以上。     

A new method for recording images in glasses

A new method for recording images in alkali silicate glasses preliminarily subjected to ion exchange in a salt melt containing silver ions is proposed. The method is based on the process of glass poling followed by heat treatment in a hydrogen atmosphere. The use of the electrode (anode) with a relief surface pattern results in the formation of an amplitude imprint (image) of this pattern under the glass surface. A trial glass sample with the amplitude pattern of the surface relief of a coin has been produced.     

In situ 4D tomography image analysis framework to follow sintering within 3D-printed glass scaffolds

We propose a novel image analysis framework to automate analysis of X-ray microtomography images of sintering ceramics and glasses, using open-source toolkits and machine learning. Additive manufacturing (AM) of glasses and ceramics usually requires sintering of green bodies. Sintering causes shrinkage, which presents a challenge for controlling the metrology of the final architecture. Therefore, being able to monitor sintering in 3D over time (termed 4D) is important when developing new porous ceramics or glasses. Synchrotron X-ray tomographic imaging allows in situ, real-time capture of the sintering process at both micro and macro scales using a furnace rig, facilitating 4D quantitative analysis of the process. The proposed image analysis framework is capable of tracking and quantifying the densification of glass or ceramic particles within multiple volumes of interest (VOIs) along with structural changes over time using 4D image data. The framework is demonstrated by 4D quantitative analysis of bioactive glass ICIE16 within a 3D-printed scaffold. Here, densification of glass particles within 3 VOIs were tracked and quantified along with diameter change of struts and interstrut pore size over the 3D image series, delivering new insights on the sintering mechanism of ICIE16 bioactive glass particles in both micro and macro scales.     

Some Features of Leaching of Two-Phase Alkali Borosilicate Glass Containing PbO

The paper reports the results of a comparative investigation into the leaching kinetics of two-phase alkali borosilicate glasses containing lead oxide in 3 M HCl solution at 100°C and the glasses free from lead oxide. It is revealed that the mechanisms of leaching of the studied glasses exhibit a common feature which resides in the fact that the temporary precipitation of the products of dissolution of the glass components within the leached layer occurs as an intermediate stage of the glass leaching. Unlike glasses free from PbO, the precipitation within the porous layer of a leached lead-containing glass is observed visually, and the presence of crystalline boron-containing precipitates in this layer is confirmed by X-ray powder diffraction analysis. Compared to glasses prepared from two-phase alkali borosilicate glasses free from PbO, the porous glasses produced from two-phase glasses containing PbO are characterized by considerably smaller sizes of micropores and their larger specific surface at the same total porosity.