Papers by Keyword: Borosilicate Glass

Abstract: The high-voltage application to silver ion-doped borosilicate glass induces the growth of silver dendritic crystals precipitation inside the substrate. This phenomenon holds significant potential for applications such as buried electric circuits and fine-hole drilling. Therefore, understanding the underlying mechanism of this phenomenon is essential for its practical utilization. In this study, we conducted in-situ observation and quantitative evaluation of the silver dendrite growth based on the temperature and the precipitation area over time. The measurements revealed that the growth rate accelerated as the precipitation progressed and increased with higher temperatures. Moreover, a model proposed here explained that these changes were attributed to the variations in the electrical resistance of the specimens and difference in the flux of the silver ions. This study provides valuable insights into the mechanism of silver dendritic precipitate growth inside glass, enabling the formation of arbitrary shapes of in-glass silver.

Abstract: The effect of additives of P₂O₅ on the solubility of molybdenum in the amorphous part of glass and on the phase composition of the crystallized part of the highly alkaline glasses of the Li₂O–(Na₂O–K₂O)–B₂O₃-SiO₂ system was studied. The comparison of the phase composition of samples with or without phosphorus prior and after annealing allowed to determine the change of solubility of molybdenum in the amorphous part of the samples and to evaluate the thermal stability of the synthesized glass-ceramic materials. It was found, that for the compositions without phosphorus and the samples without lithium, when molybdenum is added at the synthesis stage, almost all of the molybdenum is included only in the crystalline molybdates. The study has shown an increase in the solubility of molybdenum only in the structure of lithium-containing glasses with phosphorus.

Abstract: The effect of substitution of alkaline earth metals for sodium on the structure of alkali borosilicate glasses had been studied using the solid-state ¹¹B and ²⁹Si NMR spectroscopy. NMR spectra enable to evaluate the relative mole fractions of different silicon and boron structural units in studied samples. The obtained results demonstrate that alkaline earth metals increase the polymerization degree of the silicon structural units at the expense of de-polymerization of the boron units. The reason for these changes is preferential coordination of sodium and alkaline earth metals to the boron units, that increases strongly for the studied alkaline earth metals.

Abstract: The relationship between structure and refractive index for SiO₂-B₂O₃- Ta₂O₅-ZrO₂-Na₂O system glasses was investigated via Raman spectrum and V-block technology. The results showed that refractive index of the borosilicate glasses is mainly influenced by network structure such as planar [BO₃] triangle, [BO₄] tetrahedron and [SiO₄] tetrahedron. Refractive index decreases from 1.629 to 1.616 when B₂O₃ content increases from 15 mol% to 50 mol%. Na₂O component has a strong preference to provide non-bridging oxygen (NBO) atoms, which not only promotes the conversion of [BO₃] to [BO₄] unit but also depolymerizes the network structure. The refractive index has the highest value, =1.6264, when Na₂O content reaches to 28 mol%. Both ZrO₂ and Ta₂O₅ can promote structure formation of borosilicate glasses and make higher connection degree. However, the refractive index increasing with Ta₂O₅ addition is quicker than that with ZrO₂ addition.

Abstract: Unlike the traditional silicate glasses, borosilicate glasses behave differently because of the addition of boron atoms. Extensive studies have been carried out to understand the abnormal function of boron in glass network. However, it is not clear how the atomic structure of borosilicate glass changes under loading. This paper investigates the behaviour of borosilicate glass under uniaxial compression with the aid of ab initio simulations. Sodium borosilicate glass having 160 atoms and a mass density of 2.51 g/cm³ with composition 3Na₂O-B₂O₃-6SiO₂ were equilibrated first at 3500K, then at 2500K, 1500K, 1200K, 1000K, 825K and 625K. Structural analysis showed that at higher temperatures the sodium borosilicate liquid does not have a specific structure. At around 825 K (i.e. around T_g), boron network and silicon network form and remain stable even at a temperature of 625 K. When the supercooled sample at 825K was subjected to uniaxial compression, the stress along the compression direction first increases and then decreases with a change in boron structure, which could modify the behaviour of the borosilicate glass.

Abstract: Relaxation oscillation is a nonlinear dynamic phenomenon, commonly observed in viscous-plastic deformation of materials. However, it is the first time that we observed this phenomenon in the viscous flow of borosilicate glass in its super-cooled liquid region. Our investigation identified that the oscillation is caused by the particular microstructure of borosilicate glass. Specifically, the structure of borosilicate glass consists of borate-rich and silicate-rich networks. During the viscous flow, the fast deformation in borate network tends to be localized. However, the network mixing reaction between the borate-rich and silicate-rich networks can slowly relax the fast localized deformation. These two processes occur simultaneously and as a result bring about the relaxation oscillation. Based on this mechanism, the study established a physical constitutive model to predict the relaxation oscillation during the compression of borosilicate glass.

Abstract: With the development of ultra high temperature rigid heat insulation materials in the space field, it is an important strategic significance to prepare and research insulation materials of 1500°C high temperature. In our paper, the material was achieved through the process of wet suction filter forming and high temperature heat treatment, during which the high temperature alumina fiber was used as main ingredient. The fiber binder directly influences the mechanical and thermal properties of the material, and our samples were prepared using boron carbide and silicon carbide (both), borosilicate glass, alumina sol and aluminum dihydrogen phosphate as binder, respectively. The results show that borosilicate glass was the best one. Coefficient of thermal conductivity at 1000°C, lift strength and plane direction compression strength (10% compression) of the high temperature material were 0.12 W/mK, 0.35 MPa, and 1.1 MPa, respectively.

Abstract: Glasses in the system [wt%: (55-x)% SiO₂-(15+x)% B₂O₃-15% P₂O₅-10% Na₂CO₃-5% Fe₂O₃] where 15 ≤ x ≤ 40 % have been prepared with the different amount (35-55 wt%) of boron oxide. The compositions were limited by fixing the P₂O₅ at 15 wt%, Na₂CO₃ at 10 wt% and fixing the Fe₂O₃ at 5 wt%. The objective of this study is to determine the effect of boron oxide on phosphate ion released from borosilicate glass in seawater. The glass has been prepared by melting in the alumina crucible within 2 hours of soaking time at 1300 °C in the furnace and cooled to room temperature. The obtained glass was crashed and sieved with yielding a mean size of 710 μm. The samples were immersed in seawater under dynamic condition by stirring at 310 rpm. The water sample was taken 6 times at every 15 minutes until 75 minutes and analyzed using Discrete Auto Analyzer. The functional group and morphological characterization on the glass surface have been investigated using Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM). Analysis of the data indicates that the amount of 50 wt% boron was the best and optimum for the phosphate ion release which is 126.53 ppm.

Abstract: In this communication we report on the optical property of CuO nanoparticles prepared by cost effective, simplistic and environment-friendly sol-gel technique on borosilicate glass by dip coating. The particle size was analyzed by Transmission Electron Microscope (TEM) which depicted particle size of CuO ~ 5 nm. To understand the optical behavior of nanosized CuO particles on borosilicate glass tube UV-visible spectrum has been taken. Effective mass model calculations determined the size of particles as 2.26 nm, which supports the TEM analysis. Samples were also analyzed by Fourier transform infrared spectrum (FT-IR) to understand the chemical bond in detail.

Abstract: In this work, the subbituminous fly ash (SFA) in Thailand has been investigated for their compositions and crystal structures. Borosilicate glasses were prepare from SFA , B₂O₃, Na₂O and various concentration of Fe₂O₃ by melt quenching technique. The results have shown that the chemical composition comprised with SiO₂, Al₂O₃ and Fe₂O₃. The crystal structures of SFA were raised of mullite and quartz phases. The density and refractive index values of glasses were found to increase with increasing of Fe₂O₃ concentrations. The hardness values have been decreased with increasing of Fe₂O₃ content. The absorption spectra are corresponding to ferric and ferrous ions in wavelength of 440 nm and 1,050 nm and the color of glasses are green to yellow.