Glass Constituents Research Articles

Component effects of bioactive glass on corrosion resistance and in vitro biological properties of apatite-matrix coatings.

Surface modification of metallic implants is critical for improving the clinical performance of the dental and orthopedic devices. Bioactive glasses exhibit different levels of cellular function and physicochemical behavior; however, there have been few previous studies on the effect of constituents of the bioactive glasses on the in vitro osteogenic activity and corrosion resistance of apatite-based coatings. The objective of this work was to investigate the effect of SiO2, CaO, Na2O, and P2O5 on plasma-sprayed apatite coatings on Ti alloy substrates for tailoring the properties of implants making them suitable for clinical applications. The corrosion potential and corrosion current of various coatings in simulated body fluid (SBF) were examined. MG63 cell proliferation, differentiation, and mineralization of plasma-sprayed apatite-matrix coatings were evaluated. The SiO2 and CaO-containing HA (HSC) coating had a higher corrosion potential than the other three coatings, while SiO2-containing HA (HS) coating displayed the highest corrosion current among all coatings. The effect of the oxides on cell functions followed the order SiO2 > CaO > P2O5 > Na2O in terms of cell attachment, proliferation, differentiation, and mineralization. The flexibility in oxide doping may allow for the tunable biological properties and corrosion-resistant ability of the apatite coatings.

An Investigation on Acrylic Organic Coatings Including Colemanite and Zeolite for Glass Materials

Today, acrylic organic coatings are very important point for glass materials because glass has very huge area in the industry. Glass may physically be defined as a rigid. In chemically, the non-volatile inorganic oxides form from the decomposition of alkali and alkaline compounds, sand, and other glass constituents. Especially, human being uses the glass as decorative object, bottles, eye glasses, windows, and kitchen utensils in daily life. Colemanite is a borate mineral and a secondary mineral that forms by alteration of borax and ulexite. Zeolites are microporous, aluminosilicate minerals. It is commonly used as commercial adsorbents and catalysts. In this study, the acrylic organic coatings were tried to improve physical and chemical properties of glasses with using colemanite and zeolite. In addition, Taguchi Method was used to optimize the parameters for obtaining high quality and low-cost materials. The analysis results (TG-DTA, SEM) showed that the compositions of the all experiments were protected in terms of thermal properties with additives and physical appearances of the samples matched with reference sample. To conclude, additives are improved the properties of organic coatings and the results showed that the coatings produced could be evaluated in the industry.

Modifier field strength effects on densification behavior and mechanical properties of alkali aluminoborate glasses

The constituents of oxide glasses are typically classified as network formers, which form the rigid backbone of glasses, and network modifiers, which tend to either charge stabilize tetrahedral network formers or depolymerize the network. Although it is well known that the properties of glasses depend on their degree of polymerization, little is known about the role of the type of elements used as network modifiers. Here, based on a series of aluminoborate glasses comprising varying alkali oxide modifiers, we show that the glasses' structural and mechanical properties are controlled by the field strength (ratio of charge to size) of the modifiers. Namely, we show that the stiffness, hardness, and toughness depend on a fine balance between the atomic bonding energy, the packing efficiency of the atoms, and the ability of the network to densify reversibly or irreversibly, with each of these features showing a different dependence on the modifier field strength. This opens a new degree of freedom in the optimization of glass properties.

Corrosion Behavior Mechanism of Borosilicate Glasses Towards Different Leaching Solutions Evaluated by the Grain Method and FTIR Spectral Analysis Before and After Gamma Irradiation

Three selected borosilicate glasses of commercial applications were prepared and studied for their corrosion behavior by the accepted grain test method towards acidic and alkaline solutions and distilled water before and after gamma irradiation. The work was supplemented by investigating the FT infrared absorption spectra of the glasses after immersion through the KBr disc technique. The same IR measurements have been repeated after gamma irradiation. Experimental weight loss data reveal limited changes which vary with the type of leaching solution and its strength. Alkali hydroxide solutions cause more weight loss than acidic solutions due to their reactions with all glass constituents including silicate and borate species beside modifier ions while distilled water and acidic solutions react or attack the modifier ions through ion exchange corrosion behavior. FTIR spectral results show characteristic vibrational peaks due to combined silicate and borate groups which reveal an interconnected compact network structure within the mid region of wavenumber range 800–1400 cm−1. This is due to the presence of four structural building units consisting mainly of SiO4 beside BO3, BO4 and AlO4 groups. The vibrational spectra slightly change with the immersion media because of the strong and compact network structure usually identified in borosilicate glasses. The commercial glass of the Schott type is the most durable studied glass because of high silica content (75%) together with combined 10% B2O3 and 5% Al2O3. Gamma irradiation results indicate minor changes in the weight loss data due to the compact network structure of the three commercial borosilicate glasses studied.

Density and structural changes of silicate glasses under high pressure

ABSTRACT Density and structural changes of matter in their liquid or amorphous form, such as silicates melts, molecular fluids, or glasses, are of extreme importance to model the interior of planetary bodies. However, measuring the evolution of amorphous materials under extreme conditions of pressure and temperature remains challenging mainly because of the sample dimensions and the weak interaction with X-ray probes. This contribution highlights recent developments to measure the density of amorphous material, mainly silicate glasses made of light elements, to high pressure conditions. In particular, the X-ray absorption method at synchrotron sources is discussed as a new opportunity for high pressure experiments on glasses, fluids, and melts. Recent achievements using X-ray Raman scattering spectroscopy to obtain data on the local electronic environment of the main constituents of silicate glasses at high pressure are also presented. Finally, perspectives of these recent developments are discussed as well as their potential for high pressure research in the next years.

Exploring the unexpected influence of the Si:Ge ratio on the molecular architecture and mechanical properties of Al-free GICs

Germanium (Ge)-based glass ionomer cements have demonstrated the ability to balance strength with extended setting times, a unique set of characteristics for aluminum-free glass ionomer cements. However, the mechanical properties of current Ge-based glass ionomer cements significantly deteriorate over time, which jeopardizes their clinical potential. This work explores the effect of incrementally decreasing the Si:Ge ratio in the glass phase of zinc-silicate glass ionomer cements to identify potential mechanisms responsible for the time-induced mechanical instability of Ge-based glass ionomer cements. The influence of Ge was evaluated on the basis of changes in mechanical properties and molecular architecture of the cements over a 180-day period. It was observed that the compressive strength and modulus of the cements were sustained when Si:Ge ratios were ≥1:1, but when Si:Ge ratios are <1:1 these properties decreased significantly over time. These mechanical changes were independent of structural changes in the glass ionomer cement matrices, as the level of metal-carboxylate crosslinks remained constant over time across the various Si:Ge ratios explored. However, it was noted the temporal decline of mechanical properties was proportional to the increased release of degradation byproducts, in particular Ge that was released from the cements in substantially greater quantities than other glass constituents. Unexpectedly, the slowest setting cement (Si:Ge 1:1) was also the strongest; behavior that is uncommon in Si-based glass ionomer cements, supports the potential of Ge-containing glass ionomer cements as injectable bone cements in applications such as percutaneous vertebroplasty.

Structure of phosphate and iron-phosphate glasses by DFT calculations and FTIR/Raman spectroscopy

Phosphate glasses are very promising materials from the application and fundamental point of view. Properties of the glasses are strongly related to the structure which may be modified by various glass constituents. In the paper density functional theory calculations of simple phosphate structural units, chains build of them and iron-phosphate clusters are presented. Influence of a position of the unit in the chain is described. Structural changes of the units due to formation of bonds between non-bridging oxygens and iron atoms in different coordinations are shown. The optimized clusters are used then to calculate theoretical Raman and Fourier transform infrared spectra. The calculated spectra are then compared to the experimental results for an iron-phosphate glass from the pyrophosphate stoichiometry region. Finally the structural features of the glass are described.

Spectroscopic studies of Sm3+/Dy3 + co-doped lithium boro-silicate glasses

Sm3++Dy3+ co-doped lithium boro-silicate glasses were prepared by the melt quenching technique. These glasses were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and spectroscopic tools to understand the effect of Sm3++Dy3+ ions on various properties of the glasses. XRD confirmed that the prepared glasses were amorphous in nature. The FE-SEM analysis revealed the homogeneity and authenticated the various added glass constituents. On excitation with 403nm the Sm3+ glasses gave a reddish orange emission (4H9/2) while the Dy3+ glasses gave both blue (6H15/2) and yellow (6H13/2) emissions. The emission spectra of the Sm3++Dy3+ co-doped lithium boro-silicate glasses showed the emission bands of Sm3+ ions along with the Dy3+ ions. The detailed analysis confirmed that, there was no energy transfer between the Sm3+ and Dy3+ ions. The emission color could be tuned by using different excitation wavelengths for glasses prepared for the present study.

Comprehensive Isotopic and Elemental Analysis of a Multi-Oxide Glass By Multicollector ICP-MS in Isotope Substitution Studies

Multicollector ICP-MS was used to comprehensively analyze different types of isotopically modified glass created to investigate the processes of glass corrosion in the water. Analytical methods were developed for the analyses of synthesized, isotopically modified solid glass and the release of glass constituents upon contact with deionized water. To validate the methods, results from an acid digestion sample of the Analytical Reference Glass showed good agreement when compared to data from multiple prior analyses on the same glass [1]. In this paper, we present the results of the comprehensive analysis of the acid digestion of six types of isotopically modified glass and the release of glass constituents into water corrosion after one year of aqueous corrosion.

Phase composition identification and microstructure of BaTiO3-containing sodium-aluminoborosilicate glass-ceramics

Bulk glasses with a composition 20.1Na2O/23.1BaO/23.0TiO2/7.6B2O3/17.4SiO2/3Al2O3/5.8Fe2O3 containing less than 30 mol% glass-forming oxides are synthesized. Information on the valency of the glass constituents is obtained by x-ray photoelectron spectroscopy and it is concluded that all species are predominantly present in their oxidized state. Glassy samples are annealed above the glass transition temperature which leads to the crystallization of BaTiO3 for all time-temperature applied schedules. The phase composition of the glass-ceramics is studied by x-ray diffraction and the formation of cubic BaTiO3 is suggested. Temperature-dependent Raman spectroscopy confirms the presence of solely cubic BaTiO3. The microstructures of all annealed samples are similar and consist of globular interconnected particles in which nanosized BaTiO3 crystals grow randomly. The mean size of the spherical formations increases with the increasing annealing time from 200 to 600 nm. Electron microscopy suggests that during the annealing process first phase separation and then crystallization of BaTiO3 occurs.

Refinement of major- and minor-element PIXE analysis of rocks and minerals

An attempt has been made to assess the accuracy of the particle-induced X-ray emission (PIXE) fundamental parameters with standards approach to quantifying major- and minor-element constituents of silicate glasses and minerals. A deviation from linearity at low energies in the channel-energy calibration relationship was identified as a source of undesired residues in GUPIX-fitting. A correction for this effect was developed using a general-purpose spectrum fitting program and was incorporated in GUPIX. The PIXE spectra of sixteen well-characterized electron microprobe standards were then processed. Complementary electron probe micro-analysis (EPMA) measurements were used to support the comparison of the PIXE results with previous characterizations. Major element concentrations were found to differ on average from literature values as follows: SiO2 (−0.28±0.12%), Al2O3 (0.72±0.74%), MgO (0.11±0.63%), Na2O (−2.6±1.2%), K2O (1.1±0.7%), CaO (−0.35±0.37%), TiO2 (2.5±1.9%), MnO (0.8±4.7%), FeO (0.98±0.93%). These results indicate that major and minor elemental analysis can be achieved with high accuracy using the present Guelph micro-PIXE setup.

High-aluminum phosphate glasses for single-mode waveguide-typed red light source

High-aluminum phosphate (HAP) glasses with excellent chemical durability have been fabricated and investigated for thermal ion-exchanged optical waveguide. With the content adjustment, the glass constituents turn into high-aluminum area and the glass stability has been appropriately improved with more Al3+ ions cross-linked with phosphate chains, resulting in a restriction of ion-exchange rate. Consequently, stable single-mode slab waveguide operating in visible region was fabricated on Pr3+ doped HAP glass substrates by K+–Na+ ion-exchange. For Pr3+ doped HAP glasses, Judd–Ofelt intensity parameter Ω2 is solved to be 8.04×10−20cm2, implying a strong asymmetrical and covalent environment around Pr3+ in the optical glasses. Using the Ωt values, spontaneous transition probability (Arad) and branching ratio (β) of 1D2→3H4 emission are calculated to be 824.3s−1 and 13.54%, respectively, indicating that the transition emission is dominant in visible region. The radiative lifetime (τrad) and the quantum efficiency (ηq) of 1D2 level are identified to be 164.3μs and 87.7%, respectively, and the quantum yield (QY) of 1D2→3H4 transition emission is derived to be 2.3%. These results demonstrate that Pr3+ doped HAP glasses are a promising substrate in developing high-density waveguide-typed red light source, which contains attractive potential applications in medical treatment and illumination.

Uncertainty in the Surface Area of Crushed Glass in Rate Calculations

ABSTRACTSeries of 7-day Product Consistency Tests (PCTs) were conducted with ARM-1 glass using the -100+200 mesh size fraction and several sub-fractions to measure the sensitivity of the test response to the distribution of particle sizes. Separate samples were prepared for testing by dry sieving and wet sieving, and the particle size distributions and PCT responses were measured for each fraction. Triplicate tests were conducted at 90 °C using a water/glass mass ratio of 10.0 with each size fraction. Test results are evaluated regarding the sensitivity of the test response to the particle size distributions and, conversely, the uncertainty due to calculating the surface areas (and dissolution rates) by modeling the particles as spheres. These analyses show the solution feedback effects of dissolved glass constituents (i.e., the reaction affinity) counteract the effects of the glass surface areas provided by different particle size distributions on the test response. The opposing effects of the surface area on the amount of glass dissolved and on the glass dissolution rate moderate the sensitivity of the PCT response to the particle size distribution.

Assessing Impurities in Triple-Point-of-Water Cells Using a Capacitance Conductivity Test

Chemical analysis of old triple-point-of-water (TPW) cells has shown that the dominant impurities in the water are the principal constituents of borosilicate glass, which suggests the long-term downward drift observed in the realized triple-point temperature of TPW cells is caused by gradual dissolution of the glass containers. Because some of the glass constituents contribute to the electrical conductivity of the water, measurement of the conductivity provides a possible means for monitoring the long-term drift of TPW cells. This paper investigates the utility of a conductivity measurement, based on the measurement of a capacitor using the TPW cell as a dielectric, as a non-destructive means for monitoring the long-term stability of cells. The measurement exploits the cylindrical geometry of the cell and uses a two-terminal-pair coaxial electrical definition of capacitance. The results include estimates of the sensitivity of the method and examples of the long-term behavior of TPW cells, some as old as 38 years and monitored for periods of up to 10 years. It is found that the conductivity measurements correlate well with the cell age, with the drift rates increasing with time, as expected from the chemical model of glass dissolution. Measurements of temperature differences between cells show the technique can detect changes as small as \(10~\upmu \hbox {K}\), and therefore the method is a useful means of monitoring TPW cells.

Barium in intravenous solutions for administration to neonates: Origins and levels of contamination

Summary Background & aims Barium is a glass constituent and a component of plastic additives, and may migrate from containers and devices into solutions. As barium is a toxic element, all steps involved in the preparation of intravenous solutions for premature neonates in an intensive care unit were evaluated to determine to what degree, if any, they contribute to Ba load. Commercial solutions for parenteral nutrition (PN) and medications and the apparatus used for administration were analyzed for their Ba content. Bags after compounding, medications after their preparation, infusion sets, and syringes were also evaluated. Materials and methods Ba concentration was determined by atomic absorption spectrometry. Results Bags, burettes, syringes, rubber caps, and glass containers yielded Ba in levels ranging from 0.02 to 4.38 mg/g. The highest levels among the solutions were found in multivitamins, magnesium sulfate, and calcium gluconate at 262 μg/L, 193 μg/L, and 166 μg/L, respectively. Most medications did not have measurable Ba contamination. However, after dilution in syringes, all of them became contaminated, and the highest level was reached in dexamethasone samples at 1333 μg/L Ba. Compounded PN bags (n = 15) had a mean of 54.6 μg/L Ba. The content of the same bags after percolating the burette had a mean level of 94.2 μg/L Ba. Conclusion Barium is leached from container materials into solutions parenterally administered to preterm babies. The handling processes of compounding and delivering nutrition solutions and medicines increased the Ba intake by almost 3 fold in relation to its levels in the starting products.

Modeling, Structural, and Spectroscopic Studies of Cobalt-doped Lithium Phosphate Glasses and Effect of Gamma Irradiation

Undoped and cobalt oxide-doped lithium phosphate glasses were prepared by normal melt annealing technique. The structure and optical properties were investigated in order to understand the spectroscopic properties and state of cobalt in this host glass. The glass samples were characterized by combined UV-Visible and Fourier transform infrared absorption spectroscopic techniques. Ultraviolet and visible spectroscopy is used to determine the optical absorption spectra of the base undoped glass and that due to the cobalt ions in this host glass. Spectroscopic investigations were approved using the density functional theory calculations, which were employed to interpret both theoretical and experimental IR data of this glass system and to identify the main building structural groups present in these glasses. Experimental results indicate that divalent cobalt ions occupy more than one coordination state, namely, the octahedral and tetrahedral forms. The changes in the UV-Vis and infrared spectral data are discussed in relation to the change in the state of cobalt ions with glass composition or dopant concentration or structural evolution caused by the changes in glass constituents.

Experimental Assessment of Passive Capillary Wick Sampler Suitability for Inorganic Soil Solution Constituents

Determination of subsurface solute fluxes is central in critical zone (CZ) science because key processes such as bio-geochemical weathering, nutrient dynamics, and contaminant transport can be determined. With passive capillary fiberglass wick samplers (PCaps), solute, and water fluxes can be assessed; however, the presence of fiberglass can impact soil solution chemistry. To determine which solutes are suitable for sampling by fiberglass wick PCaps, flow-through experiments were performed where aqueous soil extracts were percolated through the wicks and changes in effluent solution pH, dissolved inorganic carbon (DIC), anions, major cations, and trace metals including rare earth elements (REE) were monitored. Results indicated dissolution of wicks releasing the glass constituents B, Na, Si, Ca, Mg as well as F⁻ and DIC. Barium, K, and Sr were retained, likely due to exchange reactions with either glass constituents or interlayer cations of clay colloids. Stop-flow was included to mimic precipitation events revealing increased pulse-like release of glass constituents. Results of the full-scale experiment indicate substantial contribution from wick material (59 ± 20 for Si, 92 ± 7 for Na, 29 ± 19 for Mg, and −26 ± 32 for Ca, all values in percentage of total effluent concentrations) that cannot be corrected for, hence the use of PCaps for these solutes is not recommended. A great number of other solutes were however not impacted by the presence of wicks such as most anions (Cl⁻, NO₃⁻, SO₄²⁻) and many trace metals (Al, Ti, Mn, V, Fe, Co, As, Y, Mo, Sn, Pb, U, and all REE).

Debris of potassium–magnesium silicate glass generated by femtosecond laser-induced ablation in air: An analysis by near edge X-ray absorption spectroscopy, micro Raman and energy dispersive X-ray spectroscopy

The redeposited material (debris) resulting from ablation of a potassium–magnesium silicate glass upon scanning femtosecond laser pulse irradiation (130fs, 800nm) in air environment is investigated by means of three complementary surface analytical methods. Changes in the electronic band structure of the glass constituent Magnesium (Mg) were identified by X-ray Absorption Near Edge Structure spectroscopy (XANES) using synchrotron radiation. An up-shift of ≈0.8eV of a specific Magnesium K-edge absorption peak in the spectrum of the redeposited material along with a significant change in its leading edge position was detected. In contrast, the surface left after laser ablation exhibits a downshift of the peak position by ≈0.9eV. Both observations may be related to a change of the Mg coordinative state of the laser modified/redeposited glass material. The presence of carbon in the debris is revealed by micro Raman spectroscopy (μ-RS) and was confirmed by energy dispersive X-ray spectroscopy (EDX). These observations are attributed to structural changes and chemical reactions taking place during the ablation process.

Compositional dependence of the stress-optic response in zinc tellurite glasses

The compositional dependence of the stress-optic coefficient of zinc tellurite glass was studied and correlated with local structure. The stress-optic response was determined by using the Sénarmont method, while local structure was determined by using x-ray absorption fine structure spectroscopy (XAFS) at the zinc K-edge, and Raman spectroscopy. Estimates of bond lengths d and coordination numbers NC were made and the ratio d/NC showed a strong correlation with the stress-optic coefficient, in agreement with the empirical model proposed previously by Zwanziger and co-workers. This finding is significant because both glass constituents, namely ZnO and TeO2, have complex electronic structure and are predicted by the empirical model to be at the threshold between positive and negative stress response; these glasses thus represent a rigorous check of the empirical model.

Electrical Performance of Cofired Alumina Substrates at High Temperatures

A 96% polycrystalline alumina (Al2O3) based prototype packaging system with Au thick-film metallization successfully facilitated long term testing of high temperature SiC electronic devices for over 10,000 h at 500°C previously. However, the 96% Al2O3 chip-level packages of this prototype system were not fabricated via a commercial cofire process, which would be more suitable for large scale commercial production. The cofired alumina materials adopted by the packaging industry today usually contain several percent of glass constituents to allow cofiring processes at temperatures usually lower than the regular sintering temperature for alumina. In order to answer the question of whether cofired alumina substrates can provide a reasonable high temperature electrical performance comparable to regular 96% alumina sintered at 1700°C, this paper reports on the dielectric performance of a selected high temperature cofired ceramic (HTCC) alumina substrate and a low temperature cofired ceramic (LTCC) alumina (polycrystalline aluminum oxides with glass constituents) substrate from room temperature to 550°C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. Parallel-plate capacitive devices with dielectrics of these cofired alumina and precious metal electrodes were used for measurement of the dielectric properties of the cofired alumina materials in the temperature and frequency ranges. The capacitance and AC parallel conductance of these capacitive devices were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of selected LTCC and HTCC cofired alumina substrates are presented and compared with those of 96% alumina. Metallization schemes for cofired alumina for high temperature applications are discussed to address the packaging needs for low-power 500°C SiC electronics.