Effect Of Glass Composition Research Articles

Surface acid alteration of juvenile Andean pyroclastic rocks: effect of glass composition on the development of surface fluoride-bearing minerals

Surface acid alteration of juvenile Andean pyroclastic rocks: effect of glass composition on the development of surface fluoride-bearing minerals

Effect of Composition and Phase Separation on Structure and Luminescence Properties of Tb3+ Doped Borosilicate Glasses

Two borosilicate glass series with different Na2O/B2O3 ratio and different phase separation probability have been doped with largely different concentrations of Tb3+. The addition of rare earth elements increases the phase separation tendency of borosilicate glasses, allowing to study the process in detail. Phase separation structures were also modified by annealing the glass samples at different temperatures and times. The occurring effects were studied by high resolution transmission electron microscopy (TEM) as well as with static and dynamic luminescence measurements. Strong effects of glass composition, doping concentration, and annealing on the intensity and shape of the luminescence spectra and the time-resolved luminescence are found and explained.

Correlation between composition, structure, and acousto-optic properties of As100-xSx chalcogenide glasses

Acousto-optic (AO) devices have great application potential in laser technology and network communication. Chalcogenide (ChG) glass is promising for AO devices because of its excellent infrared transparency and high AO figure of merit. Among them, As–S glasses represent the most typical and extensively studied ChG system. However, the correlation between the network structure of As–S glasses in the As-rich and S-rich regions and their AO properties remains to be investigated. In this work, the effect of glass composition and glass structure on the AO properties of As–S glasses was investigated. The gradual formation of homopolar As–As and S–S bonds leads to the weakening of the network crosslinking degree of the glass structure in the vicinity of As-rich and S-rich regions, which results in a reduction in the AO properties. In particular, the presence of long-chain As–S–As bonds in the As40S60 glass primarily causes its superior AO properties. The above results provide an important reference for the further investigation on the correlation between glass composition, structure, and AO properties and the development of As–S based AO media and devices.

Crystallization of sodium calcium silicate glass for highly transparent glass-ceramics

Sodium-calcium-silicate glasses are the most widely used glasses in architectures, photovoltaics, etc. Development of highly transparent sodium-calcium-silicate glass-ceramics is important to extend the application areas. This work investigates the effect of glass composition on the crystallization and transmittance of sodium-calcium-silicate glasses containing ZrO2. It is found that concentration of Na2O in the glasses has large effect on the crystallization behaviors and transmittance of the glass-ceramics obtained. Higher concentration of Na2O in glasses leads to lower glass transition temperature and crystallization activation energy, facilitating the bulk crystallization. Lower concentration of Na2O in glasses results in the surface crystallization of glasses. Similarity in composition of crystalline grains and glass improves the transmittance of glass-ceramics up to above 75% in the visible region, even when the grain size is as large as ~150 μm. Results reported in this work are full of significance for the development of transparent sodium-calcium-silicate glass-ceramics.

The Effect of Glass Structure on the Luminescence Spectra of Sm3+-Doped Aluminosilicate Glasses.

Peralkaline Sm3+-doped aluminosilicate glasses with different network modifier ions (Mg2+, Ca2+, Sr2+, Ba2+, Zn2+) were investigated to clarify the effect of glass composition and glass structure on the optical properties of the doped Sm3+ ions. For this purpose, the Sm3+ luminescence emission spectra were correlated with the molecular structure of the glasses derived by molecular dynamics (MD) simulations. The different network modifier ions have a clear and systematic effect on the peak area ratio of the Sm3+ emission peaks which correlates with the average rare earth site symmetry in the glasses. The highest site symmetry is found for the calcium aluminosilicate glass. Glasses with network modifier ions of lower and higher ionic radii show a notably lower average site symmetry. The symmetry could be correlated to the rare earth coordination number with oxygen atoms derived by MD simulations. A coordination number of 6 seems to offer the highest average site symmetry. Higher rare earth coordination probabilities with non-bridging oxygen result in an increased splitting of the emission peaks and a notable broadening of the peaks. The zinc containing glass seems to play a special role. The Zn2+ ions notably modify the glass structure and especially the rare earth coordination in comparison to the other network modifier ions in the other investigated glasses. The knowledge on how glass structure affects the optical properties of doped rare earth ions can be used to tailor the rare earth absorption and emission spectra for specific applications.

Effect of Glass Composition on Luminescence and Structure of CsPbBr3 Quantum Dots in an Amorphous Matrix.

Glass matrix embedding is an efficient way to improve the chemical and thermal stability of the halide perovskite QDs. However, CsPbX3 QDs exhibit distinct optical properties in different glass matrixes, including photoluminescence (PL) peak position, PL peak width, and optical band gap. In this work, the temperature-dependent PL spectra, absorption spectra, high-energy X-ray structure factor S(Q), and pair distribution function (PDF) were integrated to analyze the structural evolution of CsPbBr3 QDs in different glass matrixes. The results show that the lattice parameters and atomic spacing of CsPbBr3 QDs are affected by the glass composition in which they are embedded. The most possibility can be attributed to the thermal expansion mismatch between CsPbBr3 QDs and the glass matrix. The results may provide a new way to understand the effect of the glass composition on the optical properties of CsPbBr3 QDs in a glass matrix.

Photosensitivity of barium germano-gallate glasses under femtosecond laser direct writing for Mid-IR applications

Barium germano-gallate glasses are attractive glass hosts for photonic applications in the mid-infrared region up to 6 μm. In this work, we investigate the photosensitivity of such glasses under femtosecond laser, with an emphasize on the formation of refractive index changes. Six glasses with varying compositions (including addition of K, Na, Y, and La) were studied. We observed several transformation regimes in the pulse energy – repetition rate landscape: Type I (isotropic refractive index change) and a spatial broadening regime with a phase shift Δϕ > 2π rad at 550 nm. This translates into refractive index changes Δn > 10 −2 and is comparable to values obtained in most chalcogenide glasses. The effect of glass composition on Δϕ appears correlated to the number of non-bridging oxygen presented in the glass and is brought to evidence by monitoring the Cations/GaO 3/2 ratio. This provides a way to design a range of germano-gallate glasses suitable to imprinting high refractive index contrast.

Effect of Glass Composition on Sinterability of Copper Terminal Paste for Multilayer Ceramic Capacitors

Effect of Glass Composition on Sinterability of Copper Terminal Paste for Multilayer Ceramic Capacitors

Seeded Stage III glass dissolution behavior of a statistically designed glass matrix

AbstractThe dissolution rate of some glasses accelerates after prolonged time spent at a slow, residual dissolution rate. This phenomenon is referred to as Stage III behavior. The acceleration in glass dissolution rate linked to Stage III behavior is significant and may be the most impactful behavior to long‐term performance of glass in a repository. This work is aimed at understanding the effect of glass composition on Stage III behavior to add a level of technical defensibility to glass disposal. To this end, a set of 24 glass compositions were statistically designed, where eight glass components (SiO2, B2O3, Al2O3, CaO, Na2O, SnO2, ZrO2, and Others) have been independently varied in order to study the individual effects of each glass component. These glasses have been subjected to static dissolution tests at 90°C in deionized water and then seeded with zeolite Na‐P2 28 days into the testing to induce Stage III behavior. The response of the glasses to the zeolite seeds fell into four primary types: (1) no response to seeds; (2) an immediate linear sustained acceleration in the rate; (3) an immediate linear acceleration in the rate followed by a decrease; and (4) a progressive acceleration in the rate that is concurrent with the addition of the seeds. The main glass components observed to influence these behaviors were CaO, Al2O3, B2O3, and ZrO2, where (1) CaO influenced which glasses showed a Stage III response to seeds (high CaO: types 2, 3, and 4) or did not respond to seeds (low CaO: type 1), (2) Al2O3 and B2O3 influenced which glasses showed a sustainable Stage III response (high Al2O3: types 2 and 4) versus transitory response (low Al2O3 and high B2O3: type 3), and (3) ZrO2 concentration influenced whether glasses showed a linear (high ZrO2: type 2) versus progressive (low ZrO2: type 4) response to seeds.

Mechanism investigation on effects of glass composition on Ag/Si contact for crystalline silicon solar cells

Pb–Te–Li oxide glasses have been widely applied in front silver (Ag) paste metallization of crystalline silicon (c-Si) solar cells. In practical application, some other important glass compositions, such Bi2O3, SiO2, ZnO and so on, are often added into Pb–Te–Li oxide glasses to improve the quality of Ag/Si contact. In this paper, the significant effects of these glass compositions on the Ag/Si contact are demonstrated by discussing their influences on the formation of Ag colloids in the interface, the erosion of glass to Si, the glass phase conductivity, and the glass passivation performance at the contact interface. The results show that the addition of Bi2O3 or SiO2 into the glass may reduce the Ag/Si contact resistivity, because Bi2O3 can promote the formation of Ag colloid in the interface glass layer and increase the interface glass phase conductivity, and SiO2 can weaken the erosion ability of the glass to keep relatively high dopant concentration in the contacted Si surface. The addition of ZnO into the glass may aggravate the erosion to Si and decrease the glass phase conductivity. It is inferred that increasing Bi2O3 and SiO2 or reducing ZnO can improve the glass passivation performance at the contact interface. Through the application in Ag paste metallization, the important effects of the glass compositions on the electrical properties of solar cells are shown that Bi2O3 and SiO2 in the glasses are helpful to increase the open-circuit voltage and short-circuit current, while ZnO is very useful for raising fill factor.

Machine learning to predict refractory corrosion during nuclear waste vitrification

The goal of this study was to determine the effects of model nuclear waste glass composition on the corrosion of Monofrax® K-3 refractory, using machine learning (ML) methods for data investigation and modeling of published borosilicate glass composition data and refractory corrosion performance. First, statistical methods were used for exploration of the data, and the list of features (model terms) was determined. Several model types were explored, and the Bayesian Ridge type was the most promising due to low mean average error and mean standard error as well as high R2 value. Parameters and model results using previously identified model features and those from this study are compared. ML methods appear to give results at least as good as previously available models for describing the effects of glass composition on refractory corrosion.

Mesoporous bioactive glass composition effects on degradation and bioactivity

Mesoporous bioactive glasses (MBGs) are promising materials for regenerative medicine, due to their favorable properties including bioactivity and degradability. These key properties, but also their surface area, pore structure and pore volume are strongly dependent on synthesis parameters and glass stoichiometry. However, to date no systematic study on MBG properties covering a broad range of possible compositions exists.Here, 24 MBG compositions in the SiO2–CaO–P2O5 system were synthesized by varying SiO2 (60–90 mol %), CaO and P2O5 content (both 0 to 40 mol-%), while other synthesis parameters were kept constant. Mesopore characteristics, degradability and bioactivity were analysed.The results showed that, within the tested range of compositions, mesopore formation required a molar SiO2 content above 60% but was independent of CaO and P2O5 content. While mesopore size did not depend on glass stoichiometry, mesopore arrangement was influenced by the SiO2 content. Specific surface area and pore volume were slightly altered by the SiO2 content. All materials were degradable; however, degradation as well as bioactivity, i.e. the ability to form a CaP mineral on the surface, depended on stoichiometry. Major differences were found in early surface reactions in simulated body fluid: where some MBGs induced direct hydroxyapatite crystallization, high release of calcium in others resulted in calcite formation.In summary, degradation and bioactivity, both key parameters of MBGs, can be controlled by glass stoichiometry over a broad range while leaving the unique structural parameters of MBGs relatively unaffected. This allows targeted selection of material compositions for specific regenerative medicine applications.

Compositional study on the size distribution of nickel nanocrystals in borosilicate glasses

For three borosilicate glasses of different B-to-Si ratio, annealed under reducing atmosphere, the effect of glass composition on the size distribution of nickel nanocrystals formed therein was studied. Depth-dependent crystal size distributions were analyzed using transmission electron microscopy, while the glass structure was examined by optical and X-ray absorption spectroscopy (XAS) and related to magnetic measurements using a superconducting quantum interference device (SQUID). A B-to-Si ratio of 0.092 resulted in a uniform crystal size distribution of small width, both with depth and with time, therefore exhibiting a large share of small nanocrystals close to the superparamagnetic limit. XAS and SQUID results indicate a more effective reduction of Ni ions in the glass of higher boron oxide content due to a higher Tg and a mean lower oxidation state induced via lowering of the glass basicity.

Effects of glass composition and joining parameters on microstructural evolution and mechanical properties of Al2O3/Cu joints brazed with Bi2O3-B2O3-ZnO glass

Using nickel foil as an intermediate layer and Bi2O3-B2O3-ZnO (BBZ) glass as brazing fillers, metallurgical bonding between alumina ceramics (Al2O3) and coppers (Cu) was achieved by vacuum brazing. A series of brazing experiments were performed systematically to explore the optimal brazing process for bonding coppers and alumina ceramics with BBZ glass. Brazing occurred at different temperatures (T = 660, 680, 700, 720 °C) and dwelling times (t = 0, 20, 40, 60 min) with three kinds of BBZ glass braze. The microstructures of the joints were studied by scanning electron microscopy and the relationship between microstructures and shear strength was established.The interfacial microstructure of brazing joints varied with the shift of glass composition, while the reaction products were unaltered. Shear strength of the brazing joints depended on the distribution of ZnAl2O4 particles in the brazed seam and peaked on the BBZ10 joints obtained at 680 °C for 20 min. It were the higher ZnO content and longer brazing temperature dwelling time that made it easier for ZnAl2O4 particles to aggregate on the Al2O3 ceramics side to form a band-like distribution, which significantly reduced mechanical properties of Al2O3/Cu joints.

Fabrication and Gamma-Ray Irradiation Effect on Optical and Mechanical Properties of Germano-Silicate Glass Fibers with Inner Cladding of B and F Doped Silica Glasses

ABSTRACTThe effect of glass composition, pure silica glass, boron-doped and fluorine-doped silica glasses of inner cladding, in the germano-silicate glass core fibers on optical and mechanical properties upon the γ-ray irradiation was investigated. Enhanced radiation hardening at 1,550 nm was found in both the B- and F-doped fibers after the γ-ray irradiation with dose-rate of 1.25 kGy/h. The radiation-induced attenuation (RIA) was found to increase in the order of the B-doped fiber, the F-doped fiber, and the silica fiber. While no major influence on the refractive index of the fibers after the γ-ray irradiation was found, the residual stress was slightly changed.

The effect of glass composition on the luminescence properties of Sm3+ doped alumino silicate glasses

A large variety of more than sixty Sm3+ doped alumino silicate glass compositions were investigated for their luminescence properties in dependence of their chemical composition. To do so, mainly metaluminous and peralkaline alumino silicate glasses with the network modifiers lithium, sodium, potassium, magnesium, calcium, strontium, barium, yttrium, lanthanum, zinc, and lead were prepared. For some compositions also the effect of fluoride addition, the Al2O3/SiO2 ratio and the substitution of Al2O3 for B2O3 was investigated. A constant Sm3+ doping concentration of 1 × 1020 Sm3+/cm3 was used, which corresponds to about 0.22 mol% Sm2O3.Due to the large quantity of samples, a systematic compositional effect on the Sm3+ emission spectra could be observed: The intensity ratio of the emission peaks at 600 nm and 645 nm is decreased for network modifying ions of larger ionic radii, lower electric field strengths and for higher network modifier concentrations in the glass composition. For exceptionally low network modifier field strengths and concentrations, the emission peak at 645 nm is even stronger than the peak at 600 nm resulting in a more reddish Sm3+ emission in these glasses. The Sm3+ luminescence lifetimes generally decrease with increasing atomic weight, density and refractive index of the glasses. However, peralkaline sodium, potassium, strontium and barium alumino silicate glasses show notably higher luminescence lifetimes than other glass compositions of similar atomic weight. The lifetimes of these glasses are up to 80% higher than their respective metaluminous compositions.

Impacts of glass composition, pH, and temperature on glass forward dissolution rate

Nuclear waste glasses dissolve at the forward dissolution rate (rf) in very dilute aqueous solutions, which can isolate the impact of the glass composition from solution feedback and alteration product effects. While it has long been known that pH and temperature (T) strongly impact rf, the impacts of glass composition have remained uncertain. In this work, rf data from 19 nuclear waste glasses were used with the aim of identifying the effect of glass composition on rf. The rf values were modeled as: rf = k010–ηpHexp(−Ea/RT), with k0, η, Ea, and R, respectively, being the intrinsic rate constant, pH coefficient, apparent activation energy, and gas constant. However, no predictive correlation could be established between the individual model parameters (log[k0], η, and Ea) and glass composition for the glasses considered in this study, an outcome that was attributed to the strong positive correlation between the log[k0] and Ea parameters. Therefore, a model was fitted directly to the combined rf from all 19 glasses. This approach showed that 90% of the variation in rf data could be accounted for solely by T and pH effects. Therefore, any composition effects must be relatively small. After normalizing for differences in pH and T, the only notable differences in rf between the glasses were found to correlate with variations in the fraction of glass forming tetrahedra contributed by tetrahedral boron, f([4]B), with an abrupt threshold at a high value of f([4]B) (~0.22), where higher rf are predicted with no discernable composition effects below the threshold.

The dissolution behavior of borosilicate glasses in far-from equilibrium conditions

An area of agreement in the waste glass corrosion community is that, at far-from-equilibrium conditions, the dissolution of borosilicate glasses used to immobilize nuclear waste is known to be a function of both temperature and pH. The aim of this work is to study the effects of temperature and pH on the dissolution rate of three model nuclear waste glasses (SON68, ISG, AFCI). The dissolution rate data are then used to parameterize a kinetic rate model based on Transition State Theory that has been developed to model glass corrosion behavior in dilute conditions. To do this, experiments were conducted at temperatures of 23, 40, 70, and 90 °C and pH (22 °C) values of 9, 10, 11, and 12 with the single-pass flow-through (SPFT) test method. Both the absolute dissolution rates and the rate model parameters are compared with previous results. Rate model parameters for the three glasses studied here are nearly equivalent within error and in relative agreement with previous studies though quantifiable differences exist. The glass dissolution rates were analyzed with a linear multivariate regression (LMR) and a nonlinear multivariate regression performed with the use of the Glass Corrosion Modeling Tool (GCMT), with which a robust uncertainty analysis is performed. This robust analysis highlights the high degree of correlation of various parameters in the kinetic rate model. As more data are obtained on borosilicate glasses with varying compositions, a mathematical description of the effect of glass composition on the rate parameter values should be possible. This would allow for the possibility of calculating the forward dissolution rate of glass based solely on composition. In addition, the method of determination of parameter uncertainty and correlation provides a framework for other rate models that describe the dissolution rates of other amorphous and crystalline materials in a wide range of chemical conditions. The higher level of uncertainty analysis would provide a basis for comparison of different rate models and allow for a better means of quantifiably comparing the various models.

Effect of glass former (B2O3, SiO2, GeO2 and P2O5) addition to Fe2O3-Bi2O3 glass on pH responsivity

The effect of glass former (constituent capable to vitrify by itself such as B2O3, SiO2, GeO2 and P2O5) addition to Fe2O3-Bi2O3 (FeBi) glass on pH responsivity (pH sensitivity and pH response time) was investigated in order to develop novel pH responsive, hydrophobic glasses. Additionally, the effect of glass composition on pH sensitivity of Fe2O3-Bi2O3 glasses was investigated in order to develop contaminant-free reference electrodes with very low pH sensitivity. A small amount of B2O3 and SiO2 drastically increased the pH sensitivity. The addition of glass formers of 20 mol% provided high pH sensitivity (>90%) in any of the glass formers. Although all glass formers increased their contact angle with water for Fe2O3-Bi2O3 glass, the addition of GeO2 was most effective. Most of the Fe2O3-Bi2O3-GeO2 (FeBiGe) glasses with 20–30mol% GeO2, which serve as a working electrode, had compatibility between high pH sensitivity and a high contact angle with water (100°). However, certain Fe2O3-Bi2O3 glasses with approximately 20 mol% Fe2O3 showed low pH sensitivity (<10%). These FeBi glasses are considered to serve as contaminant-free reference electrodes, whereas KCl aqueous solution, as a contaminant, gradually leaks in commercial reference electrodes (Ag/AgCl immersed in KCl aqueous solution). Since the novel pH complex glass electrodes, consisting of a FeBiGe working electrode and a FeBi reference electrode, resist fouling of itself and serve as contaminant-free glass electrodes, these electrodes are expected to be highly useful in biological systems and drug development.

Effect of glass composition and finite size on the properties of PbO-SiO2 glasses: A comparative study of bulk and nanoglasses

The present work is an attempt to study the structural and acoustical difference between bulk and nanoglasses. Lead silicate glasses were prepared for (100-x) PbO- x SiO2 (x=40, 50, 60mol%) by melt quenching, sol-gel and hybrid method. Non-destructive ultrasonic Pulse echo method was used to measure the acoustical parameters and the obtained results were briefly analyzed based on the composition and preparation methods of the glasses. Structural and dielectric properties were studied for 50PbO-50SiO2 glasses using XRD, Raman and Impedance spectroscopy. Raman results reveal that incorporation of nanophase has considerable effect on the glass transition temperature. Impedance spectra explain the dominance of grain boundary effect with homogenous distribution. Comparative study of bulk vs. nanoglasses shows enhanced acoustical, structural and dielectric properties to be suitable for electronic and shielding applications.