Alkali Glasses Research Articles

W kwestii techniki wykonania i szkliwienia wczesnośredniowiecznych pisanek-grzechotek ze Śląska.

The article concerns early medieval egg-shaped rattles from the area of Silesia. First of all, the issue of how they were made and glazed is studied. The issues of the origin of these products and their role in the culture of ancient societies, as problems repeatedly raised by other researchers, is treated marginally. Macro- and microscopic observations, experimental studies, as well as the results of analyses of the chemical composition of glazes and petrographic tests of ceramic bodies were used to study the technology of making eggs-shaped -rattles. On their basis, the probable process of their formation and glazing was reconstructed. While the making of the ceramic base did not require extraordinary skills, the glazing and decoration of the rattles took place in several stages, requiring knowledge of advanced pottery techniques. For their decoration, a specific category of glaze was used, namely high-lead non alkali glass.

Effect of partial substitution of alkaline oxides with lithium oxide (Li2O) on low-temperature ceramic glaze

The research aims to study the effect of adding (Li2O) to an alkaline glaze containing (K2O, Na2O). Although all the alkaline oxides have common properties, each oxide has something that distinguishes it. The molecular weight of (Li2O) is two times less than that of (Na2O) and three times that of (K2O). Therefore, it is added in small proportions. In addition, it is a very strong flux, so it is not used alone, but rather replaces a part of other alkaline oxides. It was added to an alkali glass that matured at a temperature of 980CO in proportions (2.0,1.4,1.2,0.8,0.4%) instead of (Na2O), using lithium carbonate (Li2CO3) as an oxide source. The glazes mixtures were applied to a white pottery body, and the samples were fired and cooled according to programmed timings. After that, the tests and calculations were carried out: virtual and microscopic examinations, density, viscosity, surface tension, thermal expansion, hardness and scratch resistance. After analyzing and discussing the results, it was found that (Li2O) has varying effects on the properties of glazes, some of which are effective and others are less effective

Field strength effect on elastoplastic behavior of aluminoborosilicate glass: I. Elastic moduli and indentation size effect

AbstractThe modifier field strength (FS) is believed to play an important role in determining the elastic–plastic responses of aluminoborosilicate (ABS) glasses, but its effect is not well understood. Three novel alkali and three alkaline earth (AE) ABS compositions were created for this study which is the first part of two studies that explored the elastoplastic responses of these glasses. Six compositions were designed using different network modifiers (NWMs) to cover a range of cation FS. The glasses were also designed such that the concentrations of NWM and Al2O3 were similar, which maximized the three‐coordinated boron fraction in the network. It is well known that modifier FS can affect the coordination number (CN) of Al and B in an ABS glass structure, for example, a higher FS modifier can promote B3 → B4 and higher [Al5,6], but the degree of this depends on network former (NWF) ratios. Previous work used solid‐state NMR spectroscopic analysis on the current glasses to find that there was variation between [B4] and [Al4] between the two glass series (alkali vs. AE) but that was attributed to synthesis factors and no trend with FS was associated with the varying NWF CN. Further, 29Si ssNMR showed no evidence of NBOs which made sense based on composition. The conclusion, therefore, was that there was a far greater correlation with modifier FS for the increased mechanical and physical properties rather than the CN of Al and B. Part I of the current work focused on the elastic moduli, Poisson's ratio, the indentation size effect (ISE), and the bow‐in parameter. This part laid out the foundation to investigate the intersection of these elastoplastic properties with hardness and crack resistance as a function of NWM FS. Results showed that: (i) the Young's, bulk, and shear moduli increased with modifier FS, whereas Poisson's ratio did not trend with FS; (ii) the alkali glasses had a significantly higher magnitudes of ISE compared to the AE glasses; and (iii) the bow‐in parameter was load dependent and decreased with modifier FS at the highest indentation load.

Using UV-Vis-NIR absorption spectroscopy as a tool for the detection of iron and cobalt in glass: A case-study on HLLA material from the Low Countries

The early modern period is mainly characterised by High Lime-Low Alkali (HLLA) glass, a lime-rich glass made from plant or tree ashes, originating from 14th-century Germany and later used all over Europe. Attempts to link HLLA chemical subgroups to a particular point in time have failed so far. Driven by a request from the archaeological community, our research group has been exploring the feasibility of UV–Vis-NIR absorption spectroscopy as a non-destructive and in-situ applicable analysis technique for more than a decade. The main goal of this research is to provide a better understanding of the subgroups of HLLA glass and their respective dating via non-destructive means. A second topic relates to the role of cobalt as a potential indicator for either the type of applied ashes or for glass recycling.In this paper, we present the UV–Vis-NIR and LA-ICP-MS results of a total of 45 HLLA colourless glass objects or fragments, supplemented with three blue glasses from the 15th to the 17th centuries. First, we observed a correlation between iron and cobalt contents and that these two elements show more elevated concentrations starting from the middle of the 16th century. Different types of sources can be responsible, such as the type of raw materials, the tools employed, and recycling. We hypothesised that both elements were introduced through the wood or plant ashes used as fluxing agent. Then, we noted that the presence of low amounts of cobalt in colourless glass, can be observed through the analysis of the Co2+ absorption bands in the optical spectra down to 18 ppm. Next, we describe an approach to quantify iron and cobalt from the optical spectra and to date HLLA material by means of absorption spectroscopy, a valid, rapid, and non-destructive alternative for laboratory measurements. Finally, we show that the optical parameters (the Ultra-violet Absorption Edge (UVAE), the calculated Fe2+ and total iron contents, and the Co2+ absorption bands characteristics) allow discerning two glass groups: one dating to the end of the 15th-middle of the 16th centuries, and the other to the second half 16th-17th centuries. These results gain valuable information to further resolve the study on recycling, on the influence of the glassmaking tool on the glass batch composition and/or on the selection or treatment of the raw materials in HLLA glass.

Miniaturization of thermal, glass formation, and electrical properties with contrive scaling in mixed alkali (Li(1-x)Nax)5TiP3O12 (0.0 ≤ x ≤ 1.0) phosphate glasses

A NASICON based phosphate glass systems (Li(1-x)Nax)5TiP3O12 with various composition x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0 were synthesized by melt quenching method. X-ray diffraction patterns substantiate the amorphous nature. The mixed alkali effect (MAE) was explicated in thermal studies as well as in dielectric spectroscopy. The thermal analysis demonstrates that the series exhibit a MAE in their characteristic thermal parameters also. The dynamics of the ions in mixed alkali glass illustrate miniaturization of dc conductivity and maximum in their respective activation energy at x = 0.6. This decrease in conductivity in the glass composition is observed in all temperature range 273 K to 473 K and follows the same manner as glass transition temperature. The frequency dependence ac conductivity, as well as the electric modulus espouse a few interesting aspects of scaling regarding MAE.

In Vivo Analysis of the Immune Response to Strontium- and Copper-doped Bioglass.

Bioglass is a highly adoptable bone substitute material which can be combined with so-called therapeutic ions. However, knowledge is poor regarding the influence of therapeutic ions on immune reactions and associated bone healing. Thus, the aim of this work was to investigate the influence of strontium- and copper-doped bioglass on the induction of M1 and M2 macrophages, as well as vascularization. Two types of alkali glass were produced based on ICIE16 bioglass via the melt-quench method with the addition of 5 wt% copper or strontium (ICIE16-Cu and ICIE16-Sr). Pure ICIE16 and 45S5 bioglass were used as control materials. The ion release and chemical composition of the bioglass were investigated, and an in vivo experiment was subcutaneously performed on Sprague-Dawley rats. Scanning electron microscopy revealed significant differences in the surface morphology of the bioglass materials. Energy dispersive X-ray spectroscopy confirmed the efficiency of the doping process by showing the ion-release kinetics. ICIE16-Cu exhibited a higher ion release than ICIE16-Sr. ICIE16-Cu induced low immune cell migration and triggered not only a low number of M1 and M2 macrophages but also of blood vessels. ICIE16-Sr induced higher numbers of M1 macrophages after 30 days. Both bioglass types induced numbers of M2 macrophages comparable with those found in the control groups. Bioglass doping with copper and strontium did not significantly influence the foreign body response nor vascularization of the implantation bed in vivo. However, all the studied bioglass materials seemed to be biocompatible.

Structural evidence of mixed alkali effect for aluminoborosilicate glasses

The structure of mixed alkali aluminoborosilicate is quite difficult to explain due to the mixed alkali effect and interaction between multiple network formers, intermediate oxides, and network modifiers. To understand the complex behavior of these components in mixed alkali glasses, solid-state MAS NMR and Raman spectroscopy were performed. Various Raman peaks were specifically revealed, and all of which were highly associated with the degree of polymerization (DP) obtained by deconvolution of 800–1200 cm−1. A systematic change of the glass network was well explained to be a consequence of a strong relationship between DP and MAS NMR results of network formers (27Al and 11B). When alkali cations were mixed, a new characteristic of mixed alkali effect, an increase in charge compensation stability between AlO4 and smaller cation, was first observed from high correlation between full width at half maximum (FWHM) of network modifiers (7Li and 23Na) and MAS NMR data of network formers.

Molecular Dynamics Simulations of Nanolubricant Films of Alkali Glasses under Sliding Asperity Contacts

In this paper, the tribological performance of two alkali glass lubricants (sodium phosphate and sodium silicate) at the nanoscale were compared in a reactive molecular dynamics simulation. The obt...

Effects of Na2O on optical and radiation shielding properties of xNa2O-(20-x)K2O-30V2O5-50TeO2 mixed alkali glasses

In this study, the optical and gamma ray shielding properties of vanadotellurite-based quaternary glasses in the xNa2O-(20-x)K2O-30V2O5-50TeO2 system were examined. The optical band gap (Eopt) displayed an initial reduction from 2.33 to 2.30 eV (x ≤ 10 mol%), before increasing from 2.31 to 2.39 eV for x > 10 mol%, which indicated a change in non-bridging oxygen (NBO) concentration. There is an inverse relationship between Urbach energy (Eu) and Eopt. The refractive index (n) also showed an off-trend pattern within the same area (x = 10 mol%), which indicated a difference in polarizability due to changes in BO and NBO concentrations. The Phy-X software was used to analyse the radiation attenuation competence for the investigated glass systems. For the total interaction of photons between the 0.284 to 2.506 MeV energy range, the linear attenuation coefficients (LAC), the radiation protection efficiency (RPE), half-value layers (HVL) and mean free path (MFP) were determined. The increased Na2O content increased the values of LAC and RPE. The results demonstrated that the 20Na2O-30V2O5-50TeO2 composition had the most desired photon shielding properties.

Effect of local environment on stretching parameter in the mixed alkali oxyfluoro vanadate glasses: electrical modulus and structural analysis

A structural and electrical modulus study on the mixed alkali glass samples having general formula (in mol%) 40V2O5 − 30BaF2 − (30 − x) LiF – xRbF, where x = 0 – 30, in steps of 5 mol% is presented in this communication. Various vibrational bands were identified in the infrared spectra spanning 400–1200 cm−1. On the basis of shift in these bands, it was inferred that the glass network undergoes a noticeable change after 50 mol% of rubidium content. The analysis of the electrical modulus data is carried out using Kohlrausch-Williams-Watts (KWW) equation which describes the relaxation behavior of the mobile species. The variation of stretching parameter β with respect to alkali element concentration is analyzed on the basis of a combined effect of alkali ion distance and molar volume. It is found that the coupling between the mobile ions is better at 50 mol% of the alkali mixture when compared with single alkali concentrations. The contributions from fast and slow types of relaxation mechanisms were determined.

Effect of glass fibre hybridization on the water absorption and thickness of alkali treated kenaf-epoxy composites

Abstract Natural and synthetic fibre reinforced hybrid polymer composites have attracted significant attention due to their combined benefits of biodegradability and strength. Kenaf fibres have the potential to replace synthetic fibres in polymer composites due to their excellent mechanical properties. However, their use for high strength and water resistance applications are not found suitable due to their hydrophilic nature. The main aim of this study is to reduce the water absorption capacity of kenaf fibre composites through alkali treatment and glass fibre hybridization. The continuous fibre, alkali treated, unidirectional kenaf-glass–epoxy hybrid composites (K untreated, K Treated, G/K/G, G/K/G/K/G, G) were prepared by the hand lay-up method and their water absorption and thickness swelling behaviour studied. Thereafter the diffusion properties like diffusion coefficient (Dc), corrected diffusion coefficient (Dcc), sorption coefficient (Sc) and permeability coefficient (Pc) of above composites were also calculated. The results show that alkali treated hybrid composites with stacking sequence G/K/G/K/G exhibited the lowest water absorption and thickness swelling capacity in comparison to kenaf fibre composites. The alkali treated kenaf fibre composites reduced the water absorption and thickness swelling capacity by 23% and 13% respectively compared to untreated kenaf fibre composites while the glass fibre hybridization further reduced the water uptake and thickness swelling by 35% and 32% respectively as compared to alkali treated kenaf fibre composites.

Formation of Reaction Layer and Dissolution Behavior of Alkali and Alkaline-Earth Iron Phosphate Glasses in Water

Formation of Reaction Layer and Dissolution Behavior of Alkali and Alkaline-Earth Iron Phosphate Glasses in Water

Water in Alkali Aluminosilicate Glasses

To understand the influence of water and alkalis on aluminosilicate glasses, three polymerized glasses with varying ratios of Na/K were synthesized [(22. 5-x)Na2O-xK2O-22.5 Al2O3-55 SiO2 with x = 0, 7.5, and 11.25]. Subsequently, these glasses were hydrated (up to 8 wt% H2O) in an internally heated gas pressure vessel. The density of hydrous glasses linearly decreased with water content above 1 wt%, consistent with the partial molar volume of H2O of 12 cm3/mol. Near-infrared spectroscopy revealed that hydroxyl groups are the dominant species at water content of 5 wt%. The fraction of OH is particularly high in the pure Na-bearing glass compared to the mixed alkali glasses. 27Al magic angle spinning-NMR spectroscopy shows that aluminum is exclusively fourfold coordinated with some variations in the local geometry. It appears that the local structure around Al becomes more ordered with increasing K/Na ratio. The incorporation of H2O reinforces this effect. The differential thermal analysis of hydrous glasses shows a significant mass loss in the range of glass transition already during the first upscan, implying the high mobility of water in the glasses. This observation can be explained by the open structure of the aluminosilicate network and by the low dissociation enthalpy of H2O in the glasses (≈ 8 kJ/mol). The effect of the dissolved H2O on the glass transition temperature is less pronounced than for other aluminosilicate glasses, probably because of the large fraction of Al in the glasses.

Structure and glass transition temperatures of tellurite glasses

Tellurite glasses, made from the conditional glass former TeO2, show potential for use in optical applications. Alkali and alkaline earth tellurite glasses, along with single component, rapidly cooled, TeO2 are reported and studied here. Thermal properties of boron, potassium, lithium, sodium, rubidium, cesium, barium, and strontium tellurites were obtained via differential scanning calorimetry and related to structural changes observed using Raman spectroscopy. Additionally, coordination numbers of barium and strontium tellurites versus amount of modifier are also calculated. By understanding the thermal properties and coordination numbers of alkali and alkaline earth tellurites, the goal is to better elucidate the structure of amorphous TeO2.

Investigation of bending properties of E-Glass fiber reinforced polymer matrix composites for applications in micro wind turbine blades

Polymer matrix composites are divided into thermoplastic or thermosetting polymers reinforced with organic or inorganic fiber. Use of composites is increasing in the field of engineering applications due the fact that they are satisfying the required mechanical properties. The present study is made on Sandwich composite with E-Glass fiber reinforced Epoxy composite skin and Balsa wood core. E-Glass fiber reinforced composite is an immensely versatile material due to its light weight, inherent strength, weather resistance, finish and also due to variety of surface textures. Though carbon fibers are more rigid then eglass fiber, we choose e-glass for its lower cost and are better suited to extreme flex patterns. The composite consist of E-Glass fiber, epoxy resin namely Ly556 and Hardener 951. E-glass is a low alkali glass with a typical nominal composition of SiO2 54wt%, Al2O3 14wt%, CaO+MgO 22wt%, B2O3 10wt% and Na2OK2O less then 2wt%. Some other materials may also be present at impurity levels. Tensile test, compression test and three point bending test etc. has to be carried out to better understand the mechanical properties of composite material. In this study three point bending test is discussed. This study is done keeping in mind the use of E-Glass fiber and epoxy resin composite in micro wind turbine blade.

Morphological and Structural Characteristics of Sb2Se3 Thin Films Fabricated by Chemical Molecular Beam Deposition

This work presents the structural and morphological characteristics of antimony selenide (Sb2Se3) thin films, which were deposited by the chemical molecular beam deposition (CMBD) in atmospheric pressure hydrogen flow on an alkali glass substrate. It was found that the deposition temperature affected the morphology and structure of the films. At a low deposition temperature of 720 K, the film depicts a preferable crystal orientation (211), i.e., one-dimensional (1D) Sb2Se3 ribbons are aligned along the growth direction. Morphological studies show that the grain size increases with the temperature of the substrate; however, the 1D Sb2Se3 chains tend to align along the lateral direction. The Sb2Se3 films were found to have a preferable orientation (211) and polycrystalline structure. At higher substrate temperatures of 770 and 820 K, they also have a polycrystalline structure, but with an orientation (120). The studies of surface morphology show that at low substrate temperatures the samples have fine grains that have sizes of (200–300) nm, but are rather tightly packed and have 1D Sb2Se3 chains, which are aligned along the growth direction that corresponds to the orientation (211). It was found that the Sb2Se3 thin films with the orientation (211) were suitable for an absorber layer of solar cells, due to their anisotropic properties.

Ion conduction in beryllium-alumino-silicate glasses doped with sodium or sodium and lithium ions

Electrical properties of beryllium-alumino-silicate glasses containing sodium ions or sodium and lithium ions were studied with impedance spectroscopy technique over a frequency range from 10 mHz to 1 MHz and at temperature range from 213 to 473 K. The frequency- and temperature-dependent conductivity spectra of individual single alkali glasses were superimposed by means of the Summerfield scaling. Mixed-alkali glasses do not overlap into a single master curve. Glasses doped with sodium ions exhibit significantly higher values of D.C. conductivity and lower activation energy (~0.63 eV) than glasses doped with both sodium and lithium ions (~0.95 eV). The observed mixed-alkali effect can be described by the dynamic structure model (DSM). The conductivity pre-exponential factors and activation energy follow the Meyer-Neldel rule in both glass series. It was observed that the replacement of SiO2 by BeO in single cation glasses resulted in decrease in activation energy and pre-exponential factor σ0. In mixed cations glasses similar effect found for D.C. conduction process parameters was assigned to influence of both oxides BeO and Al2O3.

Alkali-Glass Behavior in Honeycomb-Type Layered Li3-xNaxNi2SbO6 Solid Solution.

Layered oxide compositions Li3-xNaxNi2SbO6 have been prepared by solid-state synthesis. A complete solid solution is evidenced and characterized by X-ray and neutron diffraction as well as 7Li and 23Na solid-state nuclear magnetic resonance spectroscopy. The transition-metal layer is characterized by the classic honeycomb Ni2+/Sb5+ ordering, whereas a more uncommon randomly mixed occupancy of lithium and sodium is evidenced within the alkali interslab space. In situ X-ray diffraction and density functional theory calculations show that this alkali disordered feature is entropically driven. Fast cooling then appears as a synthesis root to confine bidimensional alkali glass within crystalline layered oxides.

Use of Alkaline Glass in Micromechanical Sensor Structures

The use of alkali glass in micromechanical sensors, specifically, accelerometers, is shown. Alkali glass is used in the sensitive elements of the indicated devices. The main technological operation in the assembly of such sensitive elements is electrostatic bonding, also known as the anodic bonding. In this process a number of complex physical effects occur in the glass. Reliable functioning of the fabricated devices depends on the quality of the execution of the parts made of alkali glass and silicon.

Investigation of the short range order structures in sodium thioborosilicate mixed glass former glasses

The very first detailed structural examination of glasses in the sodium thioborosilicate (NTBS) mixed glass former (MGF) system is reported. As in our previous studies of MGF systems, we have fixed the ratio of the modifier, Na2S, to the total glass former (GF), BS3/2 + SiS2, and varied the ratio of the two base GFs, the pure sodium thiosilicate (NTS) and sodium thioborate (NTB) end member binary glass systems. We have found that the 0.6Na2S + 0.4[xBS3/2 + (1-x)SiS2] series with its relatively high Na2S content is continuously glass forming for all x, 0 ≤ x ≤ 1, in large ~2 mm thick samples with only modest quenching was observed. Other higher and lower Na2S content glass series were investigated, but were found to be very poor glass formers and for this reason not further studied. Further, and advantageously, but not reported on here, this high Na2S content is also associated with glasses of the highest Na+ ion conductivities in either NTS or NTB binary glasses. Infrared, Raman, and 11B and 29Si magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopies were used to examine the short-range order (SRO) structures present in these glasses as a function of x. As expected from this high modifier content, the predominate finding is that these glasses are comprised mostly of depolymerized SRO units that possess one or at most two bridging sulfurs (BSs). Indeed, the main SRO structures observed in these glasses are the Si0, B0, and Si1 SRO units which contain no BSs and one BS, respectively. The Si1 and B0 SRO units are those expected from the composition of the binary series of glasses studied here, namely 3Na/Si for x = 0 and 3 Na/B for x = 1, respectively. However, the Raman spectra shows clear evidence of the disproportionate sharing of the Na+ towards the Si SRO units. This creates significant fractions of Si0 units for intermediate compositions. Likewise, a very close inspection and deconvolution of the NMR spectra and careful attention to charge balance shows that, as seen in other MGF systems, other SRO units with more BS structures, such as B1, B2, and B4 SRO units are formed from the transfer of the Na2S from the NTB subsystem to the NTS subsystem. The E1Si2 unit appears to be a common SRO unit in NTS (and other alkali) glasses and consists of two Si possessing two non-bridging sulfurs (NBSs) but linked together by two BSs in an edge-sharing motif. Due to the presence of the E1Si2 units (50 mol% Na2S) in a compositional series that is nominally 60 mol% Na2S, we find that the lack of sufficient Si0 SRO units to account for the extra Na2S necessarily produces a small amount of free, unreacted Na2S, <10 mol% of the total sodium sulfide in the system. Interestingly, the concentration of this “free” Na2S appears to increase with increasing NTB, x, content. Finally, as in nearly all non-oxide chalcogenide glasses, we do find a small amount of contaminant oxygen, always less than ~5 mol%, as a fraction of the total O + S, O/(O + S), in all of the glasses that increases in proportion to the amount of BS3/2 in the glass. This result is consistent with our experience that the starting material BS3/2 always contains more impurity O than the SiS2 starting material.