International Journal of Applied Glass Science最新文献

Glasses in the TeO₂–Ga₂O₃–M₂O (M═Li, Na, or K) systems were synthesized by a melt-quenching technique. The glass forming areas were delimited for each system. Systematic analyses were performed on two series of samples—the first one with a constant TeO₂/Ga₂O₃ ratio of 85/15, that is, [(TeO₂)_0.85(Ga₂O₃)_0.15]_100−x[M₂O]_x with 0 ≤ x ≤ 25 (with a step of 5 mol%), the second one with a constant alkaline oxide concentration of 10 mol%, that is, [TeO₂]_90-y[Ga₂O₃]_y[M₂O]₁₀ with 5 ≤ y ≤ 15 (with step of 2.5 mol%). The values of the glass transition temperature, density, and optical transmission parameters (the positions of short- and long-wavelength absorption edge and the maximum transmittance value) were determined. The changes in these parameters were studied for varying glass compositions. In addition, the values of refractive index were measured at various wavelengths across the whole transparency region reaching from the visible up to the mid-infrared range.

Vitrification of solid technological waste is currently under investigation. For this type of waste made up of metals, minerals, and organic matters, formulation studies were carried out in the NCAS (Na₂O–CaO–Al₂O₃–SiO₂) system in order to define a vitrifying additive to treat the entire waste deposit, while maximizing the waste loading. Main challenge related to this type of waste comes from the presence of alumina in very large quantities in the glass/glass–ceramics melt, enhancing the risk of melt solidification due to a fast and massive crystallization. Melt lock-up can potentially occur at the operating temperature envisaged for the process (1400°C) and is prohibitive because it would lead to a premature stoppage of the process. The results obtained from casting tests, rheological experiments, and thermodynamic modeling enabled to provide an accurate estimation of the risk of melt lock-up for NCAS compositions. It was highlighted that the composition had a major influence on the temperature at which massive crystallization might occur. From all the results obtained, the maximum Al₂O₃ content that could be incorporated in the final material was determined to be close to 50 wt%. The composition of a vitrifying additive was also statistically designed to treat the technological waste of interest.

Next-generation nuclear reactor technologies such as the molten salt reactor utilize alkali metal fluoride salts as both fuel and coolant. In the present study, the suitability of iron phosphate glass (IPG) as a vitrification matrix for alkali metal fluoride (NaF, CaF₂) and simulated fission product loaded fluoride (NdF₃, CeF₃, SmF₃) waste has been explored. The structural change in the metal fluoride–loaded IPG has been analyzed thoroughly using Raman and fourier transform infrared (FTIR) spectroscopy. Thermal analysis showed that the stability and glass forming ability of IPG improved upon loading the same with various mixed metal fluorides. Mössbauer data and X-ray absorption spectroscopy at Fe K-edge explored the minute changes in the local structure. The effect of radiation emanating from radioactive wastes in the fluoride-loaded IPG has been scrutinized via 4.5 MeV proton beam irradiation. Our study firmly establishes the applicability of IPG as suitable vitrification matrix for radioactive metal fluoride–loaded nuclear wastes.

Flexible glass with high bending strength is a remarkable component of flexible electronic displays. However, as a brittle material, its bending properties often do not meet requirements of application. To address this challenge, the application of chemical strengthening stands out as a viable approach to significantly bolster scratch resistance and bending strength in flexible glass. This study focuses on a conventional one-step chemical strengthening method, employing molten potassium nitrate, to reinforce ultrathin aluminosilicate glass produced through the secondary down-drawing thermoforming process. Effects of ion-exchange temperature and time on mechanical properties of strengthened 110 µm flexible glass were investigated, and moreover, properties of strengthened ultrathin flexible glass with various thicknesses were compared. The results indicate that, after chemical strengthening at 380°C for 1 h, the compressive stress (CS) of 110 µm glass reaches 864.60 MPa, and the depth of layer is 15.86 µm, at which time the glass has the best bending performance and scratch resistance, and half of the faceplate spacing during glass breakage can be enhanced from 38.02 ± 2.7 to 8.40 ± 0.62 mm. For ultrathin flexible glass from 40 to 110 µm, after treatment at 380°C for 1 h, the CS of thick glass is higher than that of thin glass, and the enhancement of bending performance is better.

Lead–bismuth eutectic (LBE), a promising coolant in advanced nuclear systems, can be activated by neutrons during nuclear reactor operations. The decommissioning of nuclear facilities would generate lead–bismuth (Pb–Bi) alloy-contaminated nuclear waste. The current metallic nuclear waste treatment approach involves remelting followed by cementitious solidification. This increases the waste volume and the risk of radionuclide migration in groundwater. Therefore, this study developed a method for vitrification of Pb–Bi alloy waste. Different amounts of SiO₂ were added at 750–1100°C in the air to turn the simulated LBE waste into glass waste form. The values of the normalized elemental leaching rates (Pb, Bi, Si, Te, and Ni) determined using the 28-day static leaching test were less than .2 g m⁻² d⁻¹ and varied with SiO₂ addition. Furthermore, a three-stage evolution of the glass structure with SiO₂ addition was proposed according to the structural analysis performed using Raman and X-ray photoelectron spectroscopies. The evolution stages were as follows: (i) the stage of heavy metal transition from covalent to ionic heavy metals (7.5 wt% < SiO₂ < 15 wt%), (ii) the stage of increase in bridging oxygen (15 wt% < SiO₂ < 20 wt%), and (iii) the stage of domination of the Si–O network (20 wt% < SiO₂ < 25 wt%). The evolution of the glass structure resulted in varying glass chemical durability. Finally, the glass-forming region of (20–48)PbO–(35–70)Bi₂O₃–(7.5–25)SiO₂ (wt%) and the temperature needed to melt those glasses were determined through the melting test, where radionuclides and toxic heavy metals showed undetectable volatilization during vitrification. Hence, turning LBE waste into glass waste form will be a potential approach for treating Pb–Bi alloy nuclear waste.

Amorphous silica (SiO₂) nanoparticles (NPs) can be applied in environmental pollutant remediation, element removal, and water purification. The content of surface silanol groups in amorphous SiO₂ NPs affects the characteristics of SiO₂ NPs. However, the regulation of surface silanol group content in amorphous SiO₂ NPs below 10 nm remains a challenge. Herein, tunable surface silanol group content was achieved in disperse ultrafine amorphous SiO₂ NPs by controlling calcination and rehydroxylation. The surface silanol group content in amorphous SiO₂ NPs is low (10 nm) and can be tuned from 0% to 2.5%. The amount of naphthalene adsorbed by the SiO₂ NPs increases with increasing surface silanol group content. The surface silanol group content in SiO₂ NPs can be an effective means to tune their adsorption performance and applications.

The preparation of 0.58 Li₂S + 0.315 SiS₂ + 0.105 LiPO₃ glass, and the impacts of polysulfide and P^1P defect structure impurities on the glass transition temperature (T_g), crystallization temperature (T_c), working range (ΔT≡ T_c - T_g), fragility index, and the Raman spectra were evaluated using statistical analysis. In this study, 33 samples of this glass composition were synthesized through melt-quenching. Thermal analysis was conducted to determine the glass transition temperature, crystallization temperature, working range, and fragility index through differential scanning calorimetry. The quantity of the impurities described above was determined through Raman spectroscopy peak analysis. Elemental sulfur was doped into a glass to quantify the wt% sulfur content in the glasses. Linear regression analysis was conducted to determine the impact of polysulfide impurities and P^1P defect impurities on the thermal properties. Polysulfide impurities were found to decrease the T_g at rate of nearly 12°C per 1 wt% increase in sulfur concentration. The sulfur concentration does not have a statistically significant impact on the other properties (α = 0.05). The P^1P defect structure appears to decrease the resistance to crystallization of the glass by measurably decreasing the working range of the glasses, but further study is necessary to fully quantify and determine this.

IPS e.max Press, a lithium disilicate-based glass ceramic, is renowned in dental restorations for its mechanical strength and aesthetic appeal. This study delves into its behavior within oral environments, employing electrochemical and surface analysis techniques. By utilizing cyclic polarization curves and impedance spectroscopy, we evaluated its degradation resistance. Surface morphology, composition, and crystal stability were explored through scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX) and X-ray powder diffraction (XRD) analysis. The glass ceramic exhibited robust resistance to localized degradation across all tested electrolytes. The degradation potential (E_corr) varied with time and pH, indicating electrolyte influence. SEM/EDX affirmed oxide layer formation, while XRD confirmed a stable structure. While showcasing favorable resistance in saliva, citric acid, and lactic acid, IPS e.max Press demonstrated susceptibility to acetic acid. This comprehensive analysis enhances our understanding, providing valuable insights for the development of durable dental materials through a combination of electrochemical analysis and surface characterization.

Globally, the operational energy usage in buildings accounts for about 30% of the final energy consumption and 26% of the energy-related emissions. In 2022, the building sector recorded 132 EJ in energy usage and 9.8 Gt of CO₂ emissions. Energy-intensive space heating and air conditioning play a significant role in these statistics, with slightly over half of US home energy usage attributed to them. Thus, energy-efficient buildings, incorporating effective thermal insulation, are essential for addressing climate change. Fiberglass is the dominant insulation material used in US homes, comprising about 71% of installations. The paper discusses the fundamental aspects of heat transfer in fibrous insulation in general and fiberglass insulation in particular. The thermal performance of a fibrous insulation is characterized by an effective thermal conductivity, which combines conductive and radiative terms. The former represents heat conduction through the gas–fiber network and the latter the absorption and the scattering of thermal radiation by the fibers. The paper describes mathematical formulations for these terms and presents results showing the dependence of the effective conductivity on insulation density, fiber diameter, and temperature. The predicted values of the effective conductivity are found to be in good agreement with the measured ones.

During glass production, phase separation can result in the formation of suspended liquid droplets, which can cause changes in the system rheology. In nuclear waste vitrification context, some new glassy matrices may present this phase separation matter, but the mechanisms controlling the viscosity changes have not yet been determined. Here, we measure the viscosity of a sodium-borosilicate melt containing dissolved MoO₃ at different temperatures and subject to different applied shear strain rates. We observe that (i) the viscosity increases sharply as the temperature decreases and (ii) at any constant temperature below 1000°C, the system presents non-Newtonian response. Using transmission electron microscope observations coupled with viscosity calculations, we interpret the cause of the observed changes as the result of phase separation. We show that the viscosity increase on cooling is in excess of the predicted temperature dependence for a homogeneous melt of the starting composition. The increase is due to the formation of a second phase and is controlled by chemical and structural modifications of the matrix during the loss of the elements that form the droplets. This work provides insights into the rheology of a system composed of two composition sets due to a miscibility gap.