Borosilicate Glass Composites Research Articles

Effect of different Ba/Sr ratios on the properties of borosilicate glasses for application in 3D packaging

Borosilicate glass is a promising material for 3D system integration technology due to its high integration and adjustable CTE (coefficient of thermal expansion). However, the structure and composition of borosilicate glasses result in a relatively high melting point and dielectric loss, which hinders the wide application of such glasses. In this study, we analyze the relationship between different Ba/Sr ratios and the structure and properties of the glass. We determine and further analyze the effect of mixed alkaline earth effect on the proportion of the Qn unit, [BO3], and [SiO4] in the glass structure, and consequently, its influence on the dielectric properties. Alkaline earth metals act as network-modifying ions to reconnect the interrupted network of the glass, stabilizing the glass structure and reducing the polarization loss of the glass. Raman analysis showed that the Raman spectrum shifted towards higher frequencies as the ratio of Al2O3/RO increased, with the Raman bands at 1300 cm−1-1500 cm−1 almost disappearing, while the Raman area at 730 cm−1-830 cm−1 increased. This indicated that the [BO3] units formed a ring structure in the glass, thereby enhancing the compactness of the glass network. The thermal expansion coefficient was 4.09 ppm K−1 when the Ba/Sr ratio was 1:1, and the dielectric constant and dielectric loss were 4.3 and 1.24 × 10−3, respectively. Overall, the dielectric properties and thermal expansion coefficients of the glass can be effectively reduced by doping with alkaline-earth metals, making the borosilicate glass more suitable for three-dimensional integrated system packaging.

Research on material jetting fabrication and dielectric constant calculation of LTCC based on silica-borosilicate glass

Several material systems are available for low-temperature co-fired ceramics, and to achieve more efficient designs and applications using additive manufacturing (AM) techniques such as material jetting, the predictability of the dielectric constant of the sintered structure will significantly reduce the consumption of material development. In this work, the LTCC part was fabricated by 3D material jetting using silica-borosilicate glass LTCC ink and densified at 850°C. The borosilicate glass composition was derived from nanopowders prepared by radio frequency plasma spheronisation and configured as surface-grafted glass sols. Scanning electron microscopy results showed that silica particles were embedded in the glass matrix by a liquid phase sintering mechanism accompanied by several confined pores that were difficult to remove. A dielectric constant of around 3.78 was tested from room temperature to 100°C. Molecular dynamics sintering simulation was used to create sintered structures that matched the experimental values. The dipole moment fluctuation of the silica/glass bulk was counted to obtain an accurate value of the dielectric constant, and then the Bruggeman model based on the effective medium theory predicted the dielectric constant of the sintered body, with a prediction of 3.65, which is within 4 % difference from the measured value (3.78). The dielectric constant was predicted for different ceramic/glass compositions and sintering temperatures and found that 35 wt% and 60 wt% should be the upper and lower bounds for borosilicate glass additions to satisfy a stable structure with a relatively low dielectric constant range (3.38–4.42). In conclusion, an effective molecular dynamics approach to predict the dielectric constant of sintered bodies was developed to assist material design in LTCC AM fabrication.

Influence of the composition and structure of sodium borosilicate glasses on the optical-color characteristics of chromium aventurine glass in the presence of cobalt (II) oxide

We investigated the influence of cobalt (II) oxide additive in the amount of 1–3 mol.% on the structure and optical-color characteristics of chromium-containing glass with the following composition (mol.%): 29.6 Na2O; 19.7 В2О3; 49.3 SiO2; and 1.5 Cr2O3. The dependence of the optical-color characteristics of the glasses under study on the thermal treatment of the glass melt at a temperature of 10500C for 20 minutes was established. The thermal treatment resulted in the volumetric crystallization with the subsequent development of the aventurine effect. According to X-ray phase analysis data, the decorative effect was caused by Cr2O3 crystals. By using IR spectroscopy and differential thermal analysis, the structure of the experimental glasses was studied, and the influence of thermal treatment of glass melts on the formation of the structure of glass-ceramic material was established. Aventurine glass of dark blue-green color was obtained with a color tone =490 nm, color purity P=11.35%, and lightness L=5.454 %. The nature of the influence of cobalt (II) oxide on the optical-color characteristics of chromium-containing aventurine glass based on the Na2O–В2О3–SiO2 system is of interest for further development of new compositions of decorative ceramic glazes and enamel coatings.

Thermoviscosimetric characteristics of borosilicate glasses with regard to the promising area of low-melting compositions currently being developed for the removable small-scale melter designed by Mayak Production Association

Relevance. The need to obtain experimental data on dependence of thermoviscosimetric properties of the examined borosilicate glasses on temperature, in order to solve the problem of developing a low-melting composition of borosilicate glass for a small-scale melter designed by Mayak Production Association. Aim. To get the most complete characterization of the glasses under study using thermoviscometric measurements. Methods. Mathematical modelling, simplex-lattice design. Results and conclusions. One of the most effective methods of experiment planning, which allows, with a relatively small number of experiments, obtaining a mathematical model reflecting the dependence of the studied property of the mixture on the content of components in it, is the simplex experiment planning method. To simplify the solution of such a task, a group or groups of components are usually distinguished, in which the ratio of the mass fraction of the components does not change. In this article, three groups of components are taken – simulators of high-level radioactive waste, sodium and boron oxides, and glass frit. The authors have identified the most promising area, where the mass fraction of glass frit is from 67.5 to 75%, the mass fraction of sodium and boron is from 25 to 32.5% and the mass fraction of high-level waste components is from 0 to 20%. The paper presents the results of thermoviscometric measurements of 15 melts of low-melting borosilicate glasses of different compositions at temperatures ranging from 700 to 1,200°C. Using simplex-based mathematical models of experiment planning, domains of dependence of thermoviscosimetric characteristics of glass melts on their compositions were created. The authors identified the compositions of glass melts that are found within the viscosity limits determined as allowable for glass melt discharge during operation of the removable small-scale melter of Mayak Production Association design.

MoO3 Solubility and Chemical Durability of V2O5-Bearing Borosilicate Glass

In the vitrification of high-level radioactive liquid waste (HLW), the separation of sodium-molybdate melts is a problem because it reduces the chemical durability of the vitrified waste. A glass with both high MoO3 solubility and chemical durability is required for the safe disposal of radioactive waste. In this study, we investigate the effects of vanadium oxide on the phase separation of the molybdenum-rich phase and the water resistance of the resulting glass by phase equilibrium experiments and chemical durability test. Phase equilibrium experiments were performed on SiO2-B2O3-Al2O3-ZnO-CaO-Na2O-LiO2-MoO3 system glasses and on glasses with V2O5 added. The results showed that MoO3 solubility increased when V2O5 was added. The increase in MoO3 solubility in borosilicate melts may be associated with the viscosity-lowering effect of V2O5. Chemical durability tests were performed on borosilicate glass compositions obtained from phase equilibrium experiments. The normalized leaching rates of V2O5-bearing glasses were higher than those of other glasses. This is due to the higher network modifier/network former ratio of the glass tested. The normalized elemental mass loss of glass containing waste components increases with increasing leaching duration. This suggests that the waste component prevents the formation of a gel layer at the reaction front.

Incorporation of strontium borosilicate bioactive glass in calcium aluminate biocement: Physicomechanical, bioactivity and antimicrobial properties

Strontium borosilicate bioactive glass (SrBG) and calcium aluminate cement (CA) composites have been synthesized. The primary goal of this work is to evaluate how SrBG affects the bioactivity and physico-mechanical characteristics of CA. To fulfill this aim, SrBG was prepared by melt–quenching method and utilized as a substitute for CA by 5, 10, 15, and 20 wt%. To estimate the biological behavior of the prepared specimens, hydrᴏxyapatite layer (HA) establishment on the surface of cement paste was followed; after their immersion in a solution resembles human blood plasma (simulated body fluid solution (SBF)) at a temperature of about37 ± 0.5 °C for 4 weeks. The variations of pH, Ca and P ions concentrations in the SBF solution after soaking were determined. Compressive strength, apparent porosity, and bulk density were also measured. Via Fourier transform IR spectroscopy and X-ray diffraction analyses, the main components had been analyzed. Using scanning electron microscope (SEM) attached to energy dispersive spectroscopy, morphology of the samples was investigated. Additionally, the antimicrobial property was also assessed. The results proved that the hydrᴏxyapatite layer (HA) was developed on the surface of the prepared samples after soaking in the biological solution (SBF). It was also found that increasing SrBG percent in synthesized samples promotes the physico-mechanical characteristics and also the bioactivity performance of CA cement.Finally, these materials also showed good inhibition behavior towards bacterial biᴏfilms, against S. aureus and E. coli. after 48h. This makes these materials excellent candidates for preventing growth of bacteria after their implantation in teeth or bone.

Examining phase separation and crystallization in glasses with X-ray nano-computed tomography

X-ray nano-computed tomography (nano-CT) is a powerful technique to characterize and visualize 3 dimensional (3D) phenomena in complex glasses at the nanoscale. This technique can offer a unique opportunity to explore the intricate morphology of multicomponent glass and glass-ceramic samples, due to its low X-ray energy and high spatial resolution (down to 50 nm). In the current demonstration paper, nano-CT provided insight into crystallization and phase separation, as well as a variety of other phenomena, including corrosion, fracture, and porosity. At scales ranging from 100 to 20 μm, the microstructures of phase separation in borosilicate, complex silicate, and chalcogenide glass compositions were examined. In addition, crystallites present in simulant nuclear waste glasses, volcanic glasses, and other related samples were explored. Nano-CT analysis can add to the understanding of (1) the formation processes, (2) distributions, interactions, and compositions of phases, and (3) the mechanisms, structures, and growth of crystallization and phase separation. Nano-CT offers wide potential in the field of glass science, especially when (1) common characterization methods are insufficient, (2) simple sample preparation is required, (3) 3D rendering is needed, or (4) compelling images of small, complex features are desired.

Quantifying the densification and shear flow under indentation deformation in borosilicate glasses

AbstractBorosilicate 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.

Structural changes on the surfaces of borosilicate glasses induced by gamma‐ray irradiation

AbstractVitrification is a kind of glass that can solidify high‐level radioactive waste (HLW). As the basic material of vitrification, borosilicate glass was studied extensively. To keep HLW away from the biosphere, the tolerance of borosilicate glass to irradiation is important. In this work, various samples of borosilicate glass with different compositions were irradiated with gamma rays at ambient temperature to study their stability. The hardness, moduli, and microscopic changes on surfaces of the borosilicate glasses were measured at specific absorbed doses. Upon the gamma irradiation, the structural changes on surfaces of borosilicate glasses were identified, which were strongly influenced by the composition of borosilicate glasses. The results demonstrate that gamma irradiation, as well as beta irradiation, might strongly influence the properties of vitrification. The irradiation effects on vitrification induced by gamma irradiation should be paid more attention to than before.

HIGH-FREQUENCY ELECTROMAGNETIC PROPERTIES OF BOROSILICATE GLASSESWITH ADDITIVES OF La2O3, TiO2, ZrO2

The results of studies of high-frequency electromagnetic properties of alkaline borosilicate glasses modified with lanthanum, titanium, and zirconium oxides concerning their structure are presented. The values of the spectral reflection and transmission coefficients are experimentally measured in the frequency range 12–18 GHz. The article presents typical spectra of the complex dielectric constant of the studied glass samples inthe range of 20 Hz–1 MHz, according to which both the real and imaginary parts decrease with increasing frequency, while the imaginary part decreases much faster. It is shown that the studied glasses can be used as a vacuum-tight dielectric base with low losses in the development of high-frequency devices operating in the microwave range. The influence of the chemical composition of the experimental glasses on the value of their dielectric permittivity in the frequency ranges of 20 Hz –1 MHz and 12–18 GHzis established. The structure of the studied glasses was studied by Raman spectroscopy. The influence of lanthanum, titanium, and zirconium oxides on the degree of polymerization of the structural framework was revealed. The presence of La2O3in sodium borosilicate glass causes a decrease in the polymeriza-tion of the borosilicon-oxygen framework of glass in the entire range of introduced concentrations since La2O3is in the octahedral position and acts as a modifier in the glass structure. The intro-ductionof zirconium oxide into the composition of sodium borosilicate glass has a more significant effect on the depolymerization of the glass structure than the addition of lanthanum oxide. The most serious structural changes are observed when TiO2is introduced into the compositions of such glasses, since it acts as a glass–forming agent, forming structural motifs [TiO4], which will combine with the silicon–oxygen component, forming Si–O–Ti type bridges.

New low-temperature phosphate glasses as a host for Europium Ions

Artificial lightining, especially that of light emitting diodes, and telecommunications are penetrating every part of human lives daily. Different compositions phosphate glasses were suggested as a suitable host material for Eu3+ ions. Here rare earth metal ions act as luminescent centers also perturbing the bond order of phosphate glass network comprised of (PO4)3−, [−(O)PO3]2−, [−(O)2PO2]−, [−(O)3PO] structural units, which is indicated by Raman spectroscopy, confirming successful integration of aforementioned ions into the glass material. Glasses doped with Eu3+ ions show their typical photoluminescence spectra in low symmetry environment, consisting of the highest intensity 5D0→7F2 line. As indicated by the proceeding data, the suggested glass compositions can promisingly be employed as a low-temperature single-batch solution for the synthesis of luminescent glass matrix components, greatly reducing the energy needs compared both to silicate and borosilicate glass composites, and at the same time without the need of oxides containing expensive and heavy elements like tellurium, germanium and such. Most of the optical glass is synthesized at temperatures above 1200°C meanwhile our proposed glass compositions can be synthesized at temperatures below 1000°C which is more environmentally friendly.

Thermal treatment of nuclear fuel-containing Magnox sludge radioactive waste

Magnesium aluminosilicate and magnesium borosilicate glass formulations were developed and evaluated for the immobilisation of the radioactive waste known as Magnox sludge. Glass compositions were synthesised using two simplified bounding waste simulants, including corroded and metallic uranium and magnesium at waste loadings of up to 50 wt.%. The glasses immobilising corroded simulant waste formed generally homogenous and fully amorphous glasses, while those immobilising metallic wastes contained crystallites of UO 2 and U 3 O 8 . Uranium speciation within the glass was investigated by micro-focus X-ray absorption near edge spectroscopy and it was shown that the borosilicate glass compositions were characterised by a slightly lower mean uranium oxidation state than the aluminosilicate counterparts. This had an impact upon the durability, and uranium within glasses of higher mean oxidation states was dissolved more readily. All material showed dissolution rates that were comparable with simulant high level radioactive waste glasses, while the borosilicate-based formulations melted at a temperature suitable for modern vitrification technologies used in radioactive waste applications. These data highlight the potential for vitrification of hazardous radioactive Magnox sludge waste in borosilicate or aluminosilicate glass formulations, with the potential to achieve >95 % reduction in conditioned waste volume over the current baseline plan. • Magnesium aluminosilicate and magnesium borosilicate glass systems were synthesised to incorporate metallic uranium and magnesium, U 3 O 8 and Mg(OH) 2 • Uranium speciation within the glass was investigated by micro-focus X-ray absorption near edge spectroscopy • Borosilicate glasses possessed greater chemically durable than their aluminosilicate counterparts • All glass compositions demonstrated durability that is comparable to UK and French high level waste glass

Investigation of Borosilicate Glasses with Simulated HLW Components and Determination of Their Chemical Durability

The paper discusses the current status of the HLW vitrification technology applied at the radiochemical plant of the Mayak PA. Conceptual and technical solutions proposed to develop the technology of vitrification of various types of liquid HLW at the Mayak PA are presented. Compositions of borosilicate glasses with HLW components are described, temperatures of their melting and easy pouring are determined. Chemical durability parameters obtained for the borosilicate glasses are provided.

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.

Immobilization of contaminated sodium: an optimization study

Borosilicate glasses (BSG) are promising vitrification matrix for immobilization of contaminated sodium. Nine compositions of BSG were synthesized with O/Si ratio ranging from 3.7 to 4.8 by melt quench method. X-ray diffraction technique and scanning electron microscopy were used to ascertain the amorphous nature of glass and crystalline nature of heat treated glass. Linear thermal expansion of borosilicate glasses was determined by dilatometry. Based on maximum loading of Na2O, high density, minimum weight loss during synthesis, and volatilization studies, BSG with 45.1 SiO2 – 30.4 Na2O – 11.1 B2O3 -7.3 CaO - 6.2 ZnO (mol %) was chosen as the recommended composition and also demonstrated the immobilization of contamination of sodium with the addition of U3O8. Cold crystallization of pristine and contaminated sodium revealed the formation of Na4Ca4(Si6O18) phase during heat treatment at 1013 K in air atmosphere. Volatilization studies of above chosen composition under dynamic argon flow showed a maximum of 0.2 % weight loss, an advantage during the homogenization of the melt.

Thermoluminescence characteristics of lithium borosilicate glass doped with Sm2 O3.

Lithium borosilicate glass composite (SiO2 -Li2 CO3 -H3 BO3 ) doped with various concentrations of Sm2 O3 (0-0.7 mole %) was prepared using the melt quenching method. The investigated thermoluminescence (TL) characteristics of the prepared system revealed that the highest TL response was obtained for this glass composite at 0.05 mol% Sm2 O3 . In this study, the 0.05 mol% Sm2 O3 -doped lithium borosilicate glass composite was subjected to detailed dosimetric investigation in terms of its annealing condition, dose-response, and minimum detectable dose. The reproducibility of the response, thermal characteristics, and optical fading were also studied. The obtained results showed that the prepared glass composite had a linear dose-response over the wide gamma dose range 2Gy to 2 kGy, as well as reasonable thermal fading and excellent reproducibility. These attributes render the composite under investigation promising for utilization in radiation detection.

Tracking dynamics of glass formers and modifiers via correlation maps of molecular dynamics simulation

AbstractIn this study, we describe a method to construct a correlation map that captures the evolution of species‐specific dynamic information through the spatial correlation of high‐dimensional time‐series molecular dynamics (MD) simulation dataset for a series of borosilicate glasses. The correlation is based on ‘displacement’ between a pair of atomic configurations determined by the root mean square distance (RMSD) metric. We implement the correlation map as a quantitative visualization tool that provides a compressed representation of a high‐dimensional molecular dynamics dataset to inspect various physical aspects and capture distinct atomic dynamics—from large fluctuations to small local oscillations—for high‐temperature melt, linear cooling, and low‐temperature equilibration processes during molecular dynamics simulation of glasses. We capture species‐specific dynamics using this method that show different cooling dynamics for different glass formers and modifiers, especially the onset of slow dynamics and the variation of atomic dynamics at high temperatures. Furthermore, we show that the species‐specific atomic dynamics have structural origins that depend on the composition of the simulated borosilicate glasses. The correlation map serves as a visualization tool to rapidly survey changes in atomic configurations during different simulation conditions.

Fabrication of lead-bismuth titanate borosilicate glass ceramics and dielectric characteristics doped with GNPs

Different compositions (x) of lead-bismuth titanate borosilicate (PBTB) glasses have been synthesized using a conventional melt-quenching method in the compound 55[(PbxBi1−x)TiO3]−44[2SiO2.B2O3], (x = 0.0, 0.3, 0.5, 0.7 and 1.0) mixed with 1 mol % of graphene nanoplatelets (GNPs). XRD analysis exhibited the synthesis of clear PBTB glasses which confirmed the amorphous nature. Synthesized glasses have been converted into glass-ceramics (GCs) using a differential thermal analysis (DTA) results to understand the crystallization mechanism. XRD results described the crystalline behavior of GC samples and distinct phase formation. The surface morphology of the GCs was analyzed using a scanning electron microscope (SEM). Energy dispersive X-ray analysis (EDAX) have been also performed to verify the elemental composition of the GC sample, PBTG0.5735 F (x = 0.5). The variation in relative dielectric constant (εr) and dissipation factor (D) by increasing temperatures was obtained at different frequencies. The GC sample PTG1.0746 F (x = 1.0) showed a maximum value of dielectric constant among all glass ceramic samples.

Experimental study of bubble formation in a glass‐forming liquid doped with cerium oxide

AbstractThis work aims to study the mechanisms of oxygen bubble formation coming from redox reaction of a polyvalent element incorporated in a glass melt. Borosilicate glass composition is selected for its use as a glass matrix for nuclear waste conditioning. Cerium is selected as a polyvalent element as it may be found in nuclear waste. The chosen material is characterized in terms of physical properties which influence bubble formation and growth. A postmortem optical microscope approach is used to observe bubbles in the investigated material after thermal treatment for varying temperatures (900°C‐1100°C) and durations. To support the understanding of oxygen bubble formation, cerium speciation by X‐ray absorption near‐edge structure (XANES) and bubble gas composition are experimentally evaluated. In this article, we indicate how bubbles are formed in the investigated glass melt system. It is also demonstrated that the mechanisms that govern bubble evolution are fundamentally the same and that the plot's optimum points are strongly influenced by the temperature. These last statements are confirmed by considering some bubble features, such as bubble mean density and bubble mean diameter evolutions, and normalizing the experimental time using a characteristic residence time (tη) obtaining thereafter a dimensionless time, which is a function of the glass melt properties obtained by the physical characterizations. The impact of temperature and time on bubble formation is described.

Effect of aqueous‐based mechanical polishing on the nanoindentation response of borosilicate glasses

AbstractWhen attempting to measure material properties by sampling near‐surface volumes with techniques like nanoindentation, careful consideration of the state of the surface compared to the bulk is paramount for valid characterization. The process of surface planarization of glass in preparation for analysis is no exception. Water's general reactivity with silicate glasses has been well‐established, but under the typical conditions for mechanical polishing, the usual practical assumption is that the potential effects on measured mechanical properties are insignificant due to the short period of glass‐water interaction and the non‐extreme corrosive environment. On the contrary, in this study, it is shown that the act of polishing certain borosilicate glass compositions in an aqueous environment directly affects the nanomechanical response to several micrometers, reducing the measured elastic modulus and hardness by ~20% and ~35%, respectively. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) are used to confirm the formation of an altered, hydrated surface layer.