A micromechanical derivation of the macroscopic strength statistics for pristine or corroded/abraded float glass

The macroscopic strength of float glass is governed by the presence of micro-cracks, whose size, orientation and distribution affects the corresponding statistics. A micro-mechanically motivated model is here proposed, which spells out the connection between crack population and strength statistics, leading to generalized distributions of the Weibull type. Aging in the form of corrosion or abrasion can produce a variation of the defectiveness scenario originally present on the pristine glass surface, and we discuss how such a modification can statistically affect the macroscopic strength. A practical application is made to justify the change in strength experimentally observed passing from the “air” to the “tin” side of float glass. Assuming that the contact with the tin bath and the rollers produce a damage equivalent to the abrasion of the glass surface, we theoretically derive a bimodal Weibull statistics that agrees with the experimental evidence.     

浮法玻璃锡槽底用高强度高密度大砖的研制与应用

这种浮法玻璃锡槽底砖是用粘土熟料、莫来石细粉、氧化物超细粉和硬化剂组成的自硬性泥料制作的。采用振动成型，１２５０－１３００℃烧成。理化性能：ＳｉＯ２４５％，Ａｌ２Ｏ３４８．３８％；显气孔率１５．１％，体积密度２．３８ｇ／ｃｍ３，耐压强度７５ＭＰａ，抗折强度１３ＭＰａ，氢扩散３５０Ｐａ。所有这些性能均优于国内外同类产品指标。     

浮法玻璃熔窑卡脖处水包压入深度对玻璃液流动影响的数值研究

采用数值模拟方法,分析了置于浮法玻璃熔窑卡脖中间处的水包压入深度对窑池和卡脖内玻璃液流动状态的影响,并计算了不同水包压入深度时的卡脖出、人口处生产流及回流量。结果表明：随着水包压入深度适当增加,有利于减少玻璃液回流,降低热耗。卡脖处压入水包,玻璃液流动状态在卡脖内发生变化,水包前后的环流强度增加,有助于玻璃液均化和澄清,提高玻璃的成形质量。     

Experimental study on foam glass prepared by hydrothermal hot pressing-calcination technique using waste glass and fly ash

Foam glass is a lightweight and high-strength building and decoration material with superior performance in heat insulation, sound absorption, moisture resistance and fire protection. The use of waste glass powder and fly ash to prepare foam glass is one of the most important ways to utilize solid waste as a resource. In this study, waste glass powder and fly ash were used as raw materials to prepare foam glass by a hydrothermal hot pressing–calcination method. The effects of fly ash content (0 wt%, 10 wt%, 20 wt%, 30 wt%), heating rate (1 °C/min, 3 °C/min, 5 °C/min, 8 °C/min, 10 °C/min) and calcination temperature (600 °C, 700 °C, 750 °C, 800 °C, 850 °C, 900 °C) on the microscopic morphology, density, compressive strength, porosity and other properties of the foam glass samples were studied. Their microstructure and morphology were analyzed by thermogravimetric analysis–mass spectrometry, X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. At a fly ash content of 10 wt%, the heating rate was 5 °C/min, the calcination temperature was 800 °C, the foam glass density was 0.3 g/cm³, the compressive strength was 1.65 MPa, the total porosity was 75.5%, and the effective thermal conductivity was 0.206 W/m·K. The effective thermal conductivity models of the composite materials were used to verify the experimental data. The relationship between the thermal conductivity of foam glass materials and the related influencing factors was investigated.     

Differences in indentation and wear behaviors between the two sides of thermally tempered soda lime silica glass

Thermal tempering is an industrial process widely used to make soda lime silica (SLS) glass panels stronger and tougher. During the tempering process, the upper and bottom sides of the glass may experience different cooling rates, and thus, their properties could be different. This study characterized changes in surface composition and subsurface glass network structures as well as indentation and wear resistance properties of the air- and tin-sides of 6-mm-thick SLS window panels faced toward the upper and sliding roller sides during thermal tempering. The results showed that although the chemical and structural differences detected with X-ray photoelectron spectroscopy and specular reflection infrared spectroscopy are subtle, there are large differences in nanoindentation behaviors and mechanochemical wear properties of the SLS glass surface. The findings of this study provide further insights into the performance difference between the air- and tin-sides of the SLS glass panel treated with thermal tempering.     

Fabrication of abrasion-resistant micro-nano hierarchical structure on glass surface by a hydrothermal corrosion method

When applying an additional coating method to fabricate micro-nano hierarchical structure required for superhydrophobic function on glass surface, the hierarchical structure does generally not have good abrasion resistance, due to the weak adhesion between coating and glass surface. However, glass itself is a material with good abrasion resistance. A micro-nano hierarchical structure with honeycomb-shaped micro-armor protection on glass surface by a two-step hydrothermal corrosion method has been constructed: the first step of hydrothermal corrosion in water to construct micro-armor structure, and the second step of hydrothermal corrosion in sodium citrate aqueous solution to fabricate micro-nano hierarchical structure. The advantages of this new method are: the treatment process is simple, and there is no need to apply additional coatings. The micro-nano hierarchical structure constructed on glass surface by this method has a great abrasion resistance. After 1,000 cycles of abrasion under harsh conditions, the nano-structure on glass surface can still be remained intact. It provides a new method for fabricating abrasion-resistant micro-nano hierarchical structure on glass surface, as well as a new approach to the preparation of abrasion-resistant superhydrophobic glass.     

浮法玻璃熔窑蓄热室格子砖的损毁过程与选材

借助SEM分析了目前浮法玻璃熔窑蓄热室常用格子体在使用过程中的损毁机制,结果表明,铝硅系和AZS格子体的损毁主要是受气体侵蚀介质中的Na、SO2和Na2SO4蒸气等作用,产生霞石化或反霞石化的相变,伴随着的体积膨胀效应会使之产生裂纹、疏松和剥落;以方镁石为主晶相的格子体其损毁的原因应归因于高温环境中碱蒸气作用下方镁石的再结晶长大,以及中温条件下液态芒硝的侵蚀作用;同时,助燃空气换向产生的热震作用也可使格子体产生爆裂.文中还阐述了目前蓄热室格子体的选择方案.     

Galvanic coupling between metal substrate and polyaniline acrylic blends: corrosion protection mechanism

Coating strategies for corrosion protection based on intrinsically electronic conducting polymers, become an important research field mainly due to restrictions to the use of heavy metals, which are related to environmental problems. This work presents the corrosion protection behavior of different metals by using coatings based on acrylic blends formed by polyaniline and poly(methyl methacrylate). Raman spectroscopy revealed that the oxidation state of the PANI component of the blend at undamaged films, depends on the metal surface used as substrate. Results indicate that the degree of redox conversion of polyaniline, from emeraldine to leucoemeraldine state, strongly depends on the reducing power of metals showing a galvanic coupling between the substrate and polyaniline. On the other way, results reveal that PANI acts as an anion reservoir, which can release anions in a smart way when damage is produced on the surface of the coating forming a second physical barrier to avoid penetration of aggressive ions. This phenomenon was observed for all metal studied in this work.     

中变煮沸器1Cr18Ni9Ti列管腐蚀失效机理的研究及治理效果

针对合成氨脱碳系统中变煮沸器１Ｃｒ１８Ｎｉ９Ｔｉ列管腐蚀失效，采用动态高温模拟和高温加背压两种实验方法，研究论证了该列管在热钾碱液中发生孔蚀破坏的主要原因，阐明了腐蚀机理．提出了治理方案．     

Poly(tetrafluoroethylene)/(hexafluoropropylene) coatings for mitigating the corrosion of steel in a simulated geothermal environment

Study focused on investigating the usefulness of room temperature-curable poly(tetrafluoroethylene)/(hexafluoropropylene) as a polyfluorocarbon coating for mitigating corrosion of carbon steel in a simulated geothermal environment. Coated steel panels were exposed for up to 20 days in an autoclave containing 20,000 ppm CO₂-laden 13 wt.% NaCl solution at 200°C. The appearance of the coatings after 20 days exposure revealed that they adequately protected the underlying steel substrate against corrosion in this short-term exposure. However, the superficial layer of coating suffered hydrothermal oxidation, leading to conformational transformation of the fluorocarbon structure into a fragmental fluorocarboxylic acid derivative as the oxidation reaction product. This transformation generated three undesirable features: (1) an increase in the susceptibility of the coating surfaces to moisture; (2) a decline in the thermal stability of the coatings; (3) a reduction of the crystallinity of the polymer.     

镁尖晶石浇注料渣蚀行为与机理的研究

镁尖晶石浇注料经坩埚法抗渣后,残存试样可以分为四个段带,即挂渣层、侵蚀层、铁渗透层和硅酸盐相富集层.本实验采用SEM和EDAX研究了各段带的显微结构和基质组成,讨论了转炉终渣对浇注料的侵蚀过程和机理.     

Synthesis and growth mechanism of donut-like lead titanate particles by hydrothermal method

Tetragonal perovskite structure PbTiO₃ donut-like particles have been synthesized by a hydrothermal method in strong alkaline environment using lead nitrate (Pb(NO₃)₂) as the lead source and TiCl₄ as the titanium source. The as-prepared particles were characterized by X-ray powder diffraction (XRD) and scanning electron microscope (SEM), and it was indicated that the phase composition and particles shapes were influenced by the reaction temperature and reaction time. Based on the morphologies and phase evolutions as a function of reaction temperature or reaction time, a mechanism for the growth of the donut-like PbTiO₃ particles was proposed to involve nucleation, agglomeration, phase in situ conversion, dissolution, and recrystallization. The spherical particles were formed by primary nucleation of PbTi_0.8O_2.6 followed by agglomeration into platelets. Then, the platelet PbTi_0.8O_2.6 particles in situ converted into Pb₂Ti₂O₆ particles. Under the effects of temperature, pressure (autogenous pressure), and high solution pH value, the platelet Pb₂Ti₂O₆ particles dissolved from its center of surface and recrystallized to form PbTiO₃ nano-particles which adhered to its edges. Finally, the monocrystal donut-like PbTiO₃ particles were formed as the dissolution of Pb₂Ti₂O₆ particles completed.     

Dynamic mechanical analysis of the two glass transitions in a thermotropic polymer

A dynamic mechanical analysis has been performed on a thermotropic poly(ether ester) with biphenyl units as mesogens and spacers with methyl substituents. This polymer develops a smectic mesophase with a rather slow rate of formation, in such a way that the isotropic melt of this polymer can be easily quenched into the glassy amorphous state. A quenched amorphous sample and three specimens annealed above the glass transition for different times have been analysed. These annealed specimens exhibit different degrees of liquid crystal formation. The dynamic mechanical (and DSC) results show that the glass transition (α-relaxation) temperatures of the isotropic amorphous and anisotropic liquid crystalline states are clearly different, and when the mesophase transformation is not complete, as it happens in the two specimens annealed at intermediate times, the two glass transitions are simultaneously observed. The values of the storage modulus below the glass transition are dependent on the degree of liquid crystallinity, showing that the rigidity of the mesophase is significantly higher than the one for the amorphous component.     

Influence of the phosphate glass melt on the corrosion of functional particles occurring during the preparation of glass-ceramics

We report our findings on the impact of the glass composition on the corrosion of microparticles occurring during the preparation of glass-ceramics using the direct doping method. Microparticles (MPs) with the composition Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ with blue-green persistent luminescence were chosen as the changes in their spectroscopic properties can be related to the MPs’ corrosion. The MPs were added in phosphate-based glasses with different compositions. When using the same doping parameters, the glass system with the composition 90NaPO₃-10Na₂O (mol%) was found to be the least corrosive on the MPs whereas the glass system with the composition 90NaPO₃-10NaF (mol%) is the most corrosive on the MPs probably due to their different viscosity at 575?°C, the temperature at which the MPs are added in the glass melts.     

浮法玻璃四支撑输送辊道的安装与调试

浮法玻璃生产线冷端四支撑辊道由2组2支撑结构的辊道组成,两侧辊道之间的辊子用梅花联轴器相连。由于四支撑辊道的架子由4条大梁组成,所以辊子全部组装后我们不能在精调辊子的过程中对误差较大的某区域单独调节;而且4支撑辊道发生跑偏时修正工作量大、难度高。本文就如何保证四支撑辊道安装精度、预防玻璃跑偏,针对放线、架子组装、辊子组装及调试等工作提出了一些方法。     

An electrochemical and analytical approach to the inhibition mechanism of an amino-alcohol-based corrosion inhibitor for reinforced concrete

Laboratory investigations were performed in order to assess the effectiveness and the inhibition mechanism of an amino alcohol-based inhibitor currently used as admixture to prevent corrosion of steel in concrete. The investigation was performed in the presence of chloride ions, using solutions simulating the concrete interstitial solution. Electrochemical measurements allowed to conclude that, an inhibitor film is formed on the surface hindering the anodic activity. Furthermore, the analytical investigation through the use of X-ray photoelectron spectroscopy (XPS) shows that the inhibitor film is able to complex with the chloride ion.     

Microstructure and hydrothermal corrosion behavior of NITE-SiC with various sintering additives in LWR coolant environments

Nano-infiltration and transient eutectic phase (NITE) sintering was developed for fabrication of nuclear grade SiC composites. We produced monolithic SiC ceramics using NITE sintering, as candidates for accident-tolerant fuels in light-water reactors (LWRs). In this work, we exposed three different NITE chemistries (yttria-alumina [YA], ceria-zirconia-alumina [CZA], and yttria-zirconia-alumina [YZA]) to autoclave conditions simulating LWR coolant loops. The YZA was most corrosion resistant, followed by CZA, with YA being worst. High-resolution elemental analysis using scanning transmission electron microscopy (STEM) X-ray mapping combined with multivariate statistical analysis (MVSA) datamining helped explain the differences in corrosion. YA-NITE lost all Al from the corroded region and the ytttria reformed into blocky precipitates. The CZA material lost all Al from the corroded area, and the YZA − which suffered the least corrosion −retained some Al in the corroded region. The results indicate that the YZA-NITE SiC is most resistant to hydrothermal corrosion in the LWR environment.     

On the relationship between corrosion inhibiting effect and molecular structure

In order to relate the corrosion inhibition effect of organic compounds for steel in acid media to their molecular characteristics, SCF calculations have been performed for thiourea and nine derivatives, for two further sulphur-containing organic compounds and for urea and two derivatives. The structure of all compounds has been optimised, ionisation potential, dipole moments and the electron density distribution has been computed. It is seen that the dominant molecular parameter for the inhibition effect is the ionisation potential and that there is a clear relation between the increase in corrosion inhibition and the decrease of the ionisation potential.     

Conducting polymers for corrosion protection: What makes the difference between failure and success?

The potential of conducting polymer coatings for corrosion protection is a topic of current controversy. In general, the efficacy of conducting polymers very much depends on how they are applied and on the conditions of the corrosion experiment, i.e. depending on the exact conditions a conducting polymer may have excellent protection capability or may lead to a disastrously enhanced corrosive attack. A number of possible protection mechanisms are proposed. The most interesting corrosion protection mechanism that is currently discussed for conducting polymer-based coatings is the intelligent release of inhibitor anions. However, in many cases this does not work in the presence of larger defects. Based on scanning Kelvin probe studies of artificial defect initiated reduction and delamination of polypyrrole films in nitrogen (reduction) or air (reduction and delamination) atmospheres it will be shown in this paper that this is due to a switching from mixed anion release and cation incorporation during reduction of the conducting polymer to an exclusive cation incorporation for reduction over extended length scales. Although only results for polypyrrole are discussed here, for fundamental reasons this is postulated to be of general validity for all conducting redox polymers such as polypyrrole, polyaniline, and polythiophene. Hence, all coatings based on pure conducting polymer layers or pigments with macroscopic percolation networks will fail in the presence of larger defects, even though they may show excellent corrosion protection for smaller ones.