International Journal of Applied Glass Science最新文献

The role of the melting conditions and furnaces used to the obtained final colors has always been a question raised when investigating formulations and recipes of historical glasses. The focus of the present work is the reproduction of three recipes of red enamel glass of the manuscript by Neri, L'arte vetraria (1612) following the translation and comments by Kunckel's in Ars Vitraria Experimentalis (1679). The reproductions include the production of each individual compound of the selected recipes following instructions, and the final glass production in electric and wood-fire furnaces to assess the effect of different melting conditions. A multianalytical approach was used to fully characterize the produced samples allowing the study of the enamel chemical composition, color, crystals formations, and thermal properties. The results indicate that no significant color differences may be attributed to the melting conditions. However, it revealed that the samples produced in the electric furnace at 1200°C present a high crystallinity degree and the formation of white crystals at room temperature in a short period of time. The formation of crystals on glass is critical, and historically, to avoid it, these recipes must have been made at temperatures between 1050 and 1100°C.

Using an emittance technique with a fast CO₂ laser heating of glass samples, the high-temperature absorption spectra in the near-infrared region of ultrapure and colored (Co-, Cu-, Mn-, and Ni-doped) glasses are measured. The effects of higher glass temperatures on these absorption spectra are explained in the framework of the ligand field theory. Thus, the temperature-dependent absorption bands of the previous transition metal ions are assigned to electronic transitions among the ligand field energy levels of these ions. In particular, spectral shifts, spectral broadening, and changes in absorption strength are ascribed to changes in the structural symmetry of the ionic sites in the glass matrix and to changes of the ligand field strength at increasing temperatures.

Besides, the temperature-dependent Rosseland mean absorptions of the sulfate fined soda lime silicate glass melts, colored with the previous transition metal ions, are derived from the absorption spectra. Combining all the data, semiempirical correlations are derived, which predict the Rosseland thermal radiation properties as a function of glass temperature and of glass redox chemistry. The latter property involves the temperature-dependent concentration of the specific valency of the coloring ions, determined independently, e.g. by a Gibbs minimization redox calculation tool.

Vickers hardnesses of RO–Al₂O₃–SiO₂ glasses were measured over a broad range of compositions, ranging from ternary endpoints to mixed ratios of RO (CaO with MgO, SrO, or BaO), with the systematic variation of Al₂O₃ and SiO₂ levels. The hardnesses of CAS and MAS glasses are similar, ranging from 6.7 to 7.2 GPa, with the replacement of CaO with MgO producing a marginal increase in hardness. The substitution of SrO or BaO for CaO generally produced in a decrease in hardness down to 4.5 GPa with BaO. The sensitivity to alumina and silica levels, however, was much greater ranging from a minimum of 4.5 GPa to a maximum of ∼8.2 GPa. The correlation of the Vickers hardness with melting temperature was observed in the CAS system but generally not in the RO-blended glasses. Overall, a combined cation field strength of modifier cations determined the hardness above the critical RO blending ratio.

There is an ongoing profound shift in using glass as a primarily passive material to one that instills active properties. We believe and demonstrate that bioactive glasses (BGs) and glass–ceramics (BGCs) as functional biomaterials for cancer therapy can transform the world of healthcare in the 21st century. Melt/gel-derived BGs and BGCs can carry many exotic elements, including less common rare-earth, and trigger highly efficient anticancer properties via the combination of radiotherapy, photothermal therapy, magnetic hyperthermia, along with drug or therapeutic ions delivery. The addition of these dopants modifies the bioactivity, imparts novel functionalities, and induces specific biological effects that are not achievable using other classes of biomaterials. In this paper, we have briefly reviewed and discussed the current knowledge on promising compositions, processing parameters, and applications of BGs and BGCs in treating cancer. We also envisage the need for further research on this particular, unique class of BGs and BGCs.

In this study, elemental recovery was performed using phase separation from simulated high-level radioactive waste (HLW) glass. To cause phase separation, SiO₂ and B₂O₃ were added to the simulated HLW glass and adjusted the ratio of SiO₂: B₂O₃: other oxides to 40:50:10. The phase separated glass was immersed in aqueous solutions of 0–3 mol/L of HNO₃, H₂SO₄, and a 1:1 mixture of HCl–HNO₃ at 363 K for 20 h, and the dissolution behavior of 17 elements was examined. The relationship between the dissolved mass fraction of each element and the acid concentration in the immersion liquid could be approximated by the modified sigmoid function. The recovery of stable nuclei Se, Zr, Pd, and Cs instead of long-lived radioactive nuclei was tested using a four-stage leaching process in which the sample was immersed sequentially in four aqueous solutions at 363 K of distilled water, HNO₃, H₂SO₄, and a 1:1 mixture of HCl–HNO₃ for 20 h. It was confirmed that Se, Zr, Pd, and Cs could be recovered selectively. Furthermore, the recovery result could be predicted based on the individual dissolution results described above.

Network glass structures are commonly characterized by the network formers and their linkage but modifiers can also play an important role on various features of glass structures. In this work, we investigated the effect of cation field strength (CFS) of common modifier cations with large differences of CFS on the structures of aluminoborosilicate glasses by performing molecular dynamics (MD) simulations with recently developed potentials. It was found that modifier cations with higher CFS such as Mg²⁺ significantly reduced the fraction of fourfold coordinated boron, suggesting that the cations with higher field strength favor nonbridging oxygen generation in the silicate network and are less effective for charge compensation. The findings from our MD simulations are compared with the results from NMR and Raman spectroscopy studies in the literature as well as those from other MD simulations. Insights of the CFS effect on glass structures and the structural role of Mg²⁺ ions are gained from these simulations results and related discussions.

The glass/mold interaction is crucial for controlling the surface quality of high-precision glass products and elongating the lifespan of precious molds in hot forming techniques. Here we employ the probe tack test to separate a typical glass molding interface composed of N-BK7 glass and tungsten carbide molds at different temperatures from 655 to 690°C. The macroscale debonding behavior translates from interfacial fracture to cohesive bulk deformation as temperature increases. The glass surfaces after debonding are covered by numerous randomly distributed cavities in micrometer. With temperature increasing, the maximum depth of microcavities greatly increases from less than 0.5 to over 10 μm; the area fraction overall increases and reaches 15% at maximum. These microcavities could result from the development of localized deformation at the gas-trapping spots, due to the separation of the adhesive glass/mold interface. A large-sized cavity evolves from the cyclic growth and coalescence of small cavities. For the interfacial fracture cases, cavities mainly propagate as cracks along the interface, and thus develop into shallow disc-like shapes. However, for the cohesive cases, cavities prefer to grow in the bulk. The growth bifurcation could be governed by the competition between strain energy release rate and viscoelastic complex modulus.

Borosilicate glasses are used ubiquitously for a wide range of applications, where their mechanical properties play a critical role. However, the deformation mechanisms governing the sharp contact response of these glasses remain poorly understood. Herein, we analyze the role of elastoplastic response in determining the indentation deformation mechanisms for a range of borosilicate glass compositions. The series of glasses were made by varying the SiO₂-to-B₂O₃ molar ratio while maintaining a constant content of network modifying alkali and alkaline earth oxides. We employed nanoindentation followed by annealing below the glass transition temperature to quantify the contribution of densification and shear flow as a function of glass composition. Interestingly, we observe that the volume recovery upon annealing is inversely proportional to the hardness of the glasses. This suggests that the resistance to permanent deformation is closely related to the network connectivity of the glasses, which in turn governs the mechanism of deformation under sharp contact loading. Overall, we show the important role of alkali and alkaline earth modifiers in governing the composition-dependent indentation behavior of borosilicate glass series.

The glass composition design work leading to the discovery of highly crack resistant glasses exhibiting hydration-induced stress profiles is described. Initial hydration studies on ternary aluminosilicate glasses show the importance of potassium for facilitating hydration. Further modification of the glass composition through the incorporation of P₂O₅ increased the hydration rate such that a specimen with a 29-µm hydration depth was prepared by holding in an 85°C 85% relative humidity chamber for 65 days. Not only did this glass have a high Vickers indentation crack resistance of >20 kgf, but the sample also displayed considerable stored energy at failure. This indication of a stress profile was subsequently measured and a compressive stress (CS) of 400 MPa with a compressive depth of layer of 29 µm was found. The initially long process times were shortened using pressurized steam vessels. When held at 250°C and .3 MPa, samples can be prepared with surface CSs >300 MPa and compressive depths >30 µm in less than 8 h.