International Journal of Applied Glass Science最新文献

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.

Aluminosilicate glasses present good optical and mechanical properties, but their mechanical behavior can be further improved by thermal or chemical treatments, making them suitable for applications requiring high hardness and fracture strength, for example, laptop monitors or mobile phone screens. A lithium aluminosilicate composition was prepared, and ion exchanged in a KNO₃ bath at different temperatures for various times. Density and UV–vis transmission were measured before and after ion exchange of the glass, together with the mechanical properties, namely, Young's modulus, Poisson's ratio, shear modulus, Vickers hardness, indentation fracture toughness, and equi-biaxial bending strength, whose results were treated by Weibull statistics. The initial glass composition presented a Vickers hardness of 620 ± 10 HV, a Young's modulus of 87 ± 1 GPa, and a fracture toughness of 1.7 ± .1 MPa.m^1/2. After ion exchange, the Vickers hardness of the glass increased to average values of 716 HV for 12 h at 450°C and 728 HV for 30 h at 420°C, while the fracture toughness increased to 2.2 ± .1 MPa.m^1/2, confirming the improvement of the mechanical properties. These results have been compared with two commercial glasses: a monitor glass from a laptop computer and a glass normally used in mobile phone screens.

Reactive classical molecular dynamics simulations of sodium silicate glasses, xNa₂O–(100 − x)SiO₂ (x = 10–30), under quasi-static loading, were performed for the analysis of molecular scale fracture mechanisms. Mechanical properties of the sodium silicate glasses were consistent with experimentally reported values, and the amount of crack propagation varied with reported fracture toughness values. The most crack propagation occurred in NS20 systems (20-mol% Na₂O) compared with the other simulated compositions. Dissipation via two mechanisms, the first through sodium migration as a lower activation energy process and the second through structural rearrangement as a higher activation energy process, was calculated and accounted for the energy that was not stored elastically or associated with the formation of new fracture surfaces. A correlation between crack propagation and energy dissipation was identified, with systems with higher crack propagation exhibiting less energy dissipation. Sodium silicate glass compositions with lower energy dissipation also exhibited the most sodium movement and structural rearrangement within 10 Å of the crack tip during loading. Therefore, high sodium mobility near the crack tip may enable energy dissipation without requiring formation of structural defects. Therefore, the varying mobilities of the network modifiers near crack tips influence the brittleness and the crack growth rate of modified amorphous oxide systems.

Connecting structure with mechanical properties is needed for improving the mechanical reliability of oxide glasses. Although the mechanical properties of silicate and borosilicate glasses have been intensively studied, this is not the case for phosphate and borophosphate glasses. To this end, we here study the structure, density, glass transition, hardness, elasticity, and cracking behavior of lithium borophosphate glasses. The glasses are designed with different B/P ratios to access different boron and phosphorus speciation. The introduction of boron in the phosphate network increases the average network rigidity because of the reduction in the fraction of nonbridging oxygens as well as the exchange of phosphate groups with more constrained BO₄ groups. These structural changes result in an increase in density, Vickers hardness, glass transition temperature, and Young's modulus, and a decrease in Poisson's ratio for higher B₂O₃ content. Furthermore, the increase in network rigidity and atomic packing density results in a lower ability of the glasses to densify upon indentation, resulting in an overall decrease in crack initiation resistance. Finally, we find an increase in the fraction of trigonal boron units in the high-B₂O₃ glasses, which has a significant effect on atomic packing density and Vickers hardness.

A set of in situ measurement equipment of large aperture strong light element based on the principle of laser scattering is established. The size and distribution of defects (damage points) can be judged by the laser scattering signal. The maximum scanning range is 700 mm*1000 mm. The type and size of defects are directly obtained by scanning the quartz sample with a diameter of 100 mm. The types of defects are pitting and scratches, and the width of the scratches and the diameter of the pitting are mostly in the range of 0–10μm. The processing time could reach 31.06s. The device can realize the on-line in situ measurement of large aperture optical elements, and has the advantages of fast response speed and high measurement accuracy.