Quaternary Glasses Research Articles

Laser-induced effects on dielectric relaxation of multi-component Se76Te20Sn2Cd2 chalcogenide glass

In present work, we have synthesized a novel quaternary Se76Te20Sn2Cd2 glass in bulk form. Four laser light sources from UV–Vis-IR region have been used to investigate the laser-induced effects on the dielectric properties to check the candidature of this material for possible application in optoelectronics. The temperature and frequency dependence of dielectric constant (ε′) and dielectric loss (ε″) of unexposed and laser-exposed exposed samples are studied over audible frequency range (1–10 kHz). The comprehensive investigation proves the applicability of the Guintini's theory of dielectric dispersion for the present dielectric loss data.

Electrical conductivity and modulus formulation in zinc modified bismuth boro-tellurite glasses

The ac conductivity of zinc modified tellurium based quaternary glasses having composition 60 TeO2–10 B2O3–(30 − x) Bi2O3–x ZnO; x = 10, 15, 20, 25 and 30 has been investigated in the frequency range 10−1–105 Hz and in temperature range 483–593 K. Frequency and temperature dependent ac conductivity found to obey Jonscher power law modified by Almond–West. DC conductivity, crossover frequency and frequency exponent have been estimated from the fitting of the experimental data of conductivity with Jonscher power law modified by Almond–West. The ac conductivity and its frequency exponent have been analyzed by various theoretical models. In presently studied glasses ac conduction takes place via tunneling of overlapping large polaron tunneling. Activation energy is found to be increased with increase in zinc content and dc conduction takes place via variable range hopping proposed by Mott with some modification suggested by Punia et al. The value of the stretched exponent (β) obtained by fitting of $$ M^{{\prime \prime }} $$ reveals the presence of non-Debye type relaxation. Scaling spectra of ac conductivity and electric modulus collapse into a single master curve for all compositions and temperatures, reveals the presence of composition and temperature independent conduction and relaxation process in these glasses. Activation energy of conduction (W) and electric modulus (E R ) are nearly equal, indicating that polaron have to overcome the same energy barrier during conduction as well as relaxation processes.

Observation of switching behavior in some multi-component glasses of Se-Te-Sn-Pb system

The present work reports the detection of new switching materials in lead containing selenium rich quaternary glasses. The results of current-voltage characteristics in some multi-component glasses of Se-Te-Sn-Pb system confirms the memory switching behavior in parent Se-Te-Sn glass that changes into threshold switching behavior after incorporation of Pb.

Composition, Elastic Property and Packing Efficiency Predictions for Bulk Metallic Glasses in Binary, Ternary and Quaternary Systems

The results of database based on the efficiency packed model for metallic glasses. The database contains the atomic radii information as well as elastic properties of the most commonly used alloying elements, permitting composition, packing efficiency and elastic property predictions to be made for binary, ternary and quaternary bulk metallic glasses. Twenty different alloys per system (binary, ternary and quaternary) experimentally reported in the literature were compared with those estimated by the database. Comparison charts and diagrams showed good agreement between the composition predictions and those reported from the experimentally processed metallic glasses. The elastic properties predictions could be used to elaborate Blackman diagrams in order to know, in advance, the intrinsic toughness that the investigated alloys might present. The database is intended for designing bulk metallic glasses. Finally, some quaternary alloys were experimentally produced based on the prediction obtained with the database, showing a glassy phase. The microhardness values obtained experimentally of the Zr57.52Ag10.62Al10.62Co21.24, Zr57.19Al10.7Ni10.7Cu21.41 and Hf60.22Al9.95Cu9.95Ni19.89alloys, are 3.8, 4.0 and 3.6 GPa, respectively. The Young´s modulus calculated using microhardness values (E/Hv = 20) are closed to the values obtained by the mixing rules.

Raman, FTIR, thermal and optical properties of TeO2-Nb2O5-B2O3-V2O5 quaternary glass system

A series of quaternary glass systems with the composition 79TeO2-(20−x)Nb2O5-xB2O3-1V2O5 was prepared using the melt quench technique. Such studies as optical absorption, Raman, FTIR spectroscopy, EPR and DSC were carried out on the glass system. The physical properties, such as density (ρ) and molar volume (VM), were determined. The Urbach energy (ΔE), optical band gap (Eopt), optical basicity (Λ), refractive index (n) and electron polarizability (α) of the glasses were determined from optical absorption data. Spin-Hamiltonian parameters of VO2+ ions were calculated from the EPR data. With the gradual substitution of B2O3 at the expense of Nb2O5, the density and optical band gap of the glasses decreased, and the electronic polarizability increased. EPR spectra revealed that VO2+ occupies an octahedral site with tetrahedral compression. Spin-Hamiltonian parameters g|| and g⊥ increased as B2O3 content increased in the glass. The glass transition temperature (Tg) also decreased as the B2O3 content in the glass increased.

Local atomic structure of quaternary Fe-based metallic glass studied by X-ray diffraction, Mössbauer spectroscopy and Reverse Monte Carlo modeling

The atomic structure of Fe42Co20Nb8B30 glassy alloy was investigated using synchrotron high-energy X-ray diffraction (XRD), Mössbauer spectroscopy (MS) and Reverse Monte Carlo modeling (RMC). The RMC method basing on the results of XRD measurements was used for evaluating interatomic distances and coordination numbers in the local structure of quaternary alloy. The coordination numbers for Fe–Fe atomic pairs were additionally determined using Mössbauer spectroscopy investigations and Gonser et al. approach. The measured Mössbauer spectra of glassy alloy were decomposed into subspectra representing average Fe–Fe coordination numbers. A layer with thickness of 0.5nm was extracted from the RMC configuration box containing 8000atoms and short-range ordering in the investigated glassy alloy was analyzed within this fragment. Coordination polyhedra for Fe–Fe, Co–Fe, B–Fe and Nb–Fe atomic pairs are represented by the Bernal's tetrahedra and octahedral as well by the monocapped square antiprism with one atom missing and B-centered clusters related to the tricapped trigonal prisms. The presence of clusters with five-fold coordination for the Fe–Fe pairs is confirmed by analysis of the Mössbauer spectra using the Gonser approach.

Electron beam irradiation on lead fluoroborate glasses doped by europium ions

We report here the effects of high-energy electron beam (energy: 7.5 MeV, dose: 150 kGy) over thermal, structural and mechanical nature of Eu3+-doped lead fluoroborate quaternary glasses built using melt–mold technique. Glass transformation temperatures [glass transition (T g), onset of crystallization (T x), crystallization (T c) and melting temperature (T m)] through differential scanning calorimetry (DSC), density (ρ), molar volume (V m), Vickers microhardness (H) and different elastic constants [Young’s modulus (E), bulk modulus (K), shear modulus (G) and Poisson’s ratio (µ)] were analyzed to study the thermal and mechanical effects on amorphized borate glasses and check its reaction on stability and vitreous network of the glass samples. The constants of elasticity were calculated in terms of Makishima–Mackenzie model. We observed that the glass matrix showed a compact network from 0 to 0.5 mol% and then from 1.0 to 2.5 mol% the structure loosened. On the basis of the different atomic changes upon doping and irradiation, it is proved that the present glass system is stable till 300 °C and could be utilized in building optoelectronics devices. These dependencies are the consequences of various precursors (preparation environment, irradiation effect, heating during DSC) inherited in the glassy structure.

Preparation and properties of quaternary CoMoPB bulk metallic glasses

A new series of Co80−xMoxP14B6 (x = 7, 9, and 11 at%) bulk glassy alloys were successfully prepared by a combination method of fluxing treatment and J-quenching technique. The glass-forming ability (GFA) of the obtained Co-based alloys is sensitive to the Mo content substituted for Co, and the maximum attainable diameter for a fully amorphous state can reach 4.5 mm at x = 9. The compressive tests show that the obtained Co-based BMGs exhibit a compressive strength of 3.3–3.9 GPa, but nearly zero compressive plasticity. The new Co-based BMGs possess good soft magnetic properties, and their saturated magnetization values decrease from 47 emu/g (0.45 T) to 14 emu/g (0.14 T) with increasing the content of the Co substitute from 7 at% to 11 at%, which may be attributed to the anti-ferromagnetic coupling between the Mo and Co atoms. Because of their good GFA, high Co content, few constituting elements, and relatively high strength, the obtained Co-based BMGs (especially Co71Mo9P14B6 BMG) can be considered promising as starting alloys to develop the new Co-based BMGs for the advanced structural and functional applications.

Bioactivity of quaternary glass prepared from bentonite clay

Alkoxysilane precursors are the most widely used silica source for sol–gel preparation of silicate-based bioactive glass. However, due to their high cost, alternative sources such as bentonite clay are desirable. In the present work, bentonite clay was reacted with sodium hydroxide (NaOH) to extract sodium metasilicate (Na2SiO3). The obtained Na2SiO3 was converted to gel which was then sintered at 950 ℃ for 3 h to give the bioactive glass in the quaternary composition SiO2–NaO–CaO–P2O5. The resulting glass was incubated in simulated body fluid (SBF) for 0–7 days to evaluate the bioactivity. Furthermore, glass samples were characterized before and after SBF study by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Results obtained showed the presence of Na2Ca2Si3O9 (combeite) crystal as the major crystalline phase and the formation of hydroxyapatite (HA) and hydroxycarbonated apatite (HCA) on the surface of the glass after immersion in SBF. The material showed potentials for application as scaffold in bone tissue repair.

Optical, elastic properties and DTA of TNZP host tellurite glasses doped with Er3+ ions

Novel quaternary tellurite glasses within the composition 75TeO2–10Nb2O5–10ZnO–5PbO (TNZP) doped with the following Er3+ concentrations: 2500, 3750, 5000, 6250, 7500 and 8750 ppm have been prepared by using conventional melt quenching method. The thermal parameters, such as the glass transition temperature (Tg), crystallization temperature (Tc) and thermal stability (ΔТ) were determined. It is described that this system shows a stable glass formation, high thermal stability and low tendency crystallization. The linear refractive index, n, the optical energy gap, Eg, the nonlinear refractive index, n2, two photon absorption TPA, third order susceptibility, χ(3), of prepared glasses have been determined. Moreover elastic properties like longitudinal (λ), shear (μ), Bulk (β) and Young's (Y) moduli, Poisson's ratio, Debye temperature, and the microhardness of the glasses were evaluated by measuring both longitudinal and shear velocities using the pulse-echo overlap technique at 5 MHz. The present glasses is a promising candidate for optical application.

Linear release of strontium ions from high borate glasses via lanthanide/alkali substitutions

The effect of increasing substitutions of La2O3:Na2O on the structure (11B MAS NMR) and properties, specifically strontium (Sr) ion release from five quaternary borate glass compositions (B2O3–SrO–Na2O–La2O3) was studied. To examine component ion release, samples were extracted under simulated physiological conditions at 37°C for five extraction time points (24, 72, 168, 336 and 720h). A linear release profile for strontium was provided by composition LB102 (70B2O3–20SrO–6Na2O–4La2O3) for up to 720h. 11B MAS NMR was used to investigate the impact of La2O3:Na2O substitution on the boron structure and speciation. Substitutions appeared to have minor effects on borate speciation, with the only change being a decrease in the proportion of BO4 at maximum La2O3 loading (70B2O3–20SrO–10La2O3). These data further demonstrate the possible utility of high boron glasses as controllable degradable materials for the delivery of therapeutic metal ions, such as strontium.

Structural Characterization and Compositional Dependence of Optical Properties of Ge16Se52Te32−x Sb x (x = 0, 2, 4, 6, 8) Glassy Alloys

Antimony-substituted Ge-Se-Te quaternary chalcogenide glasses have been synthesized using the melt quench technique. The bonding arrangements in the glassy matrices have been studied through infrared spectra in the spectral region from 50 cm−1 to 300 cm−1. The effect of Sb addition on the optical properties has also been studied using ultraviolet–visible–infrared (UV–Vis–IR) spectroscopy on thin films of uniform thickness. The materials possess high refractive index and tunable bandgap with low values of optical loss. They also possess good infrared transparency regions, high refractive index, and low optical bandgap, making them suitable for use in photonic applications.

Electronic transport and relaxation studies in bismuth modified zinc boro-tellurite glasses

The ac conductivity of tellurium based quaternary glasses having composition 60 TeO2 – 10 ZnO – (30 − x) B2O3 – xBi2O3; x = 0, 5, 10, 15 and 20 has been investigated in the frequency range 10−1 Hz to 105 Hz and in the temperature range 483 K–593 K. The frequency and temperature dependent ac conductivity increase with increase in bismuth content and found to obey Jonscher's universal power law. The dc conductivity, crossover frequency and frequency exponent have been estimated from the fitting of the experimental data of conductivity with Jonscher's universal power law. In the studied glasses the ac conduction may be described by overlapping of large polaron tunneling model. The activation energy is found to be decrease with increase in bismuth content and variable range hopping (VRH) proposed by Mott with some modification suggested by Punia et al. is more or less suitable to explain dc conduction. The value of the stretched exponent (β) obtained by fitting of M″ reveals the presence of non-Debye type of relaxation in the presently studied glass samples. Scaling spectra of electric modulus (M′ and M″) collapse into a single master curve for all the compositions and temperatures. The values of activation energy of electric modulus (ER) and conduction (W) are nearly equal for all the studied glasses, indicating that the polaron have to overcome the same energy barrier during conduction as well as relaxation processes. The conduction and relaxation process in the presently studied glass samples are composition and temperature independent.

Quaternary Ti–Zr–Be–Ni bulk metallic glasses with large glass-forming ability

Abstract The glass-forming ability (GFA) of Ti–Zr–Be ternary alloys is dramatically improved by partially replacing Be with Ni. Centimeter-scale fully amorphous samples can be obtained in a wide Ni content range of 4 at.%–12 at.%. In particular, some of the developed Ti–Zr–Be–Ni alloys exhibit a critical diameter up to 20 mm, which is larger than that of other quaternary Ti-based bulk metallic glasses (BMGs). Moreover, Ni addition also enhances the yield strength and compressive plastic strain of Ti–Zr–Be alloys obviously. Based on the experimental results, the effect of substituting elements addition on the glass-forming ability of Ti–Zr–Be alloys has been systematically investigated and an empirical composition design method for the development of novel Ti-based BMGs with large GFA has been proposed.

Composition dependent structural and optical properties of PbF2–TeO2–B2O3–Eu2O3 glasses

Boric oxide based quaternary glasses in the system PbF2–TeO2–B2O3–Eu2O3 have been prepared by melt quenching technique. Density, molar volume, FTIR, UV–Vis techniques were used to probe the structural modifications with incorporation of europium ions in the glass network. An increase in glass density & decrease in molar volume (Vm) values proved the structural changes occurring in coordination of boron atom [conversion of BO3 units to BO4]. This resulted in the increase of the compaction of the prepared glasses with increase in Eu2O3 contents. The amorphous natures of the samples were ascertained by XRD and metallization criterion (M) studies. XPS study showed the values of core-level binding energy [O1s, Eu3d, Eu4d, Te3d, Te4d, Pd4f, Pb5d, O1s, and F1s] of (PbF2–TeO2–B2O3–Eu2O3) the glass matrix. The frequency and temperature dependence of dielectric properties of present glasses were investigated in the frequency range of 1Hz–10MHz and temperature range of 313–773K. The study of dielectric measurements proved good insulating and thermal stability of the prepared glasses. At room temperature, dielectric loss [tanδ] values were negligibly small for prepared glasses and increased with increase in temperature. FTIR spectroscopy results were in good agreement with optical band energy gap, density, molar volume and hardness values revealing network modifications caused by europium ions in the glass structure.

Temperature Stability and Physical Properties of Bi2O3-B2O3-ZnO-RHA Glass System

Rice husk ash (RHA) is a product from the burning of the rice husk and it become a significant material for glass preparation due to high amount of amorphous silica that can be produced. From the recent studies, the highest amount of silica is observed at 550°C at 6 hours which is 99.36% by XRF detection. Nevertheless, the amount of silica decreasing proportionally if the temperature profile is higher than 550°C and the time taken is more than 6 hours. Quaternary glasses are prepared using melt-quenching method using the highest amount of silica from RHA combined with Bismuth Oxide (Bi2O3), Boron Oxide (B2O3), and Zinc Oxide (ZnO). The ratio of quaternary glass that used are 30%SiO2: 20%B2O3: xZnO : (50-x)%Bi2O3 (% mole) ; where x= 10,20,30,40. The physical properties and glass transition temperature (Tg) profiles are determined using standard measurement instrument. Moreover, the density measured will enhance the verification of Oxygen Packing Density for prepared quaternary glasses.

Preferential sputtering in phosphate glass systems for the processing of bioactive coatings

Phosphate based glass (PBG) coatings of up to 2.6μm thick have been applied by RF magnetron sputtering for their potential in promoting osseointegration and as an ion delivery system for biomaterials. The processing behaviour of PBG under ion bombardment has been investigated, notably the phenomena of preferential sputtering. The relative sputtering yields for the elements within quaternary and quinternary glass oxides have been found to be dependent upon the chemical bonding and momentum exchange interactions at the surface, subsurface layers of the target material. This led to preferential sputtering in the order, P<Fe<Ca<Mg<Na, based on the absolute changes from 6 target compositions to their respective coating compositions, showing a reduction in P2O5 and Fe2O3 of between 10.3–15.2, 0.2–0.6mol% respectively and an increase in MgO, CaO, and Na2O of 4.8–6.0, 0.1–3.8, and 3.0–6.9mol% respectively. The order primarily corresponded to the relative dissociation energies of the network modifying ions bound to oxygen of (818.0 or 1227.0 for Fe), 928.0 for Ca, 788.0 for Mg, and 257.0kJmol−1 for Na. The deposition rates from targets T1–T6 varied between 1.59–1.93nmmin−1 at a constant pressure of 1.05Pa. Increasing the pressure from 0.28 to 1.87Pa led to improved stoichiometric transfer from target to coating.

Strontium- and calcium-containing, titanium-stabilised phosphate-based glasses with prolonged degradation for orthopaedic tissue engineering.

Strontium- and calcium-releasing, titanium-stabilised phosphate-based glasses with a controlled degradation rate are currently under development for orthopaedic tissue engineering applications. Ca and/or Sr were incorporated at varying concentrations in quaternary phosphate-based glasses, in order to promote osteoinduction. Ti was incorporated at a fixed concentration in order to prolong degradation. Glasses of the general formula (P2O5)–(Na2O)–(TiO2)–(CaO)–(SrO) were prepared via the melt-quench technique. The materials were characterised by energy-dispersive X-ray spectroscopy, X-ray diffraction, 31P magic angle spinning nuclear magnetic resonance, Fourier transform infrared spectroscopy, differential thermal analysis and density determination. The dissolution rate in distilled water was determined by measuring mass loss, ion release and pH change over a two-week period. In addition, the cytocompatibility and alkaline phosphatase activity of an osteoblast-like cell line cultured on the surface of glass discs was assessed. The glasses were shown to be amorphous and contained Q1, Q2 and Q3 species. Fourier transform infrared spectroscopy revealed small changes in the glass structure as Ca was substituted with Sr and differential thermal analysis confirmed a decrease in crystallisation temperature with increasing Sr content. Degradation and ion release studies also showed that mass loss was positively correlated with Sr content. These results were attributed to the lower electronegativity of Sr in comparison to Ca favouring the formation of phosphate-based mineral phases. All compositions supported cell proliferation and survival and induced at least 2.3-fold alkaline phosphatase activity relative to the control. Glass containing 17.5 mol% Sr had 3.6-fold greater alkaline phosphatase activity than the control. The gradual release of Ca and Sr supported osteoinduction, indicating their potential suitability in orthopaedic tissue engineering applications.

Physical, structural and optical characterizations of borate modified bismuth–silicate–tellurite glasses

Quaternary bismuthate glasses with compositions xB2O3–(80−x) Bi2O3–15SiO2–5TeO2 have been prepared by melt-quench technique. X-ray diffraction studies were performed to ascertain the amorphous nature of samples. The density, molar volume and crystalline volume decrease with increase in B2O3 content whereas the glass transition temperature shows the reverse trend. The Raman and FTIR spectra of the studied glasses indicate that B2O3 has been found to exist in the form of BO3 trigonal and BO4 tetrahedral structural units and vibrations corresponding to these structural units increase with increase in B2O3 content. SiO2 is present in the form of SiO4 tetrahedral structural units and TeO2 in the form of TeO3 structural units. Bismuth plays the role of network modifier [BiO6 octahedra] as well as network former [BiO3 pyramids] for all the glass compositions. The optical band gap energy has been calculated from the fitting of both Mott and Davis’s model and Hydrogenic excitonic model with the experimentally observed absorption spectra. A good fitting of experimental data with HEM indicates the excitonic formation in the studies glass system. The values of optical band gap energy show nonlinear behavior due to the structural changes that take place in the present glass samples. The Urbach energy calculated using Urbach empirical formula for studied glass samples suggest the possibility of reduction in defect concentrations. The metallization criterion of the presently studied samples suggests that the prepared glasses may be potential candidates for nonlinear optical applications.

Composition-structure-properties relationship of strontium borate glasses for medical applications

We have synthesized TiO2 doped strontium borate glasses, 70B2O3-(30-x)SrO-xTiO2 and 70B2 O3 -20SrO(10-x)Na2 O-xTiO2 . The composition dependence of glass structure, density, thermal properties, durability, and cytotoxicity of degradation products was studied. Digesting the glass in mineral acid and detecting the concentrations of various ions using an ICP provided the actual compositions that were 5-8% deviated from the theoretical values. The structure was investigated by means of (11)B magic angle spinning (MAS) NMR spectroscopy. DSC analyses provided the thermal properties and the degradation rates were measured by measuring the weight loss of glass disc-samples in phosphate buffered saline at 37°C in vitro. Finally, the MTT assay was used to analyze the cytotoxicity of the degradation products. The structural analysis revealed that replacing TiO2 for SrO or Na2 O increased the BO3/BO4 ratio suggesting the network-forming role of TiO2 . Thermal properties, density, and degradation rates also followed the structural changes. Varying SrO content predominantly controlled the degradation rates, which in turn controlled the ion release kinetics. A reasonable control (2-25% mass loss in 21 days) over mass loss was achieved in current study. Even though, very high concentrations (up to 5500 ppm B, and 1200 ppm Sr) of ions were released from the ternary glass compositions that saturated the degradation media in 7 days, the degradation products from ternary glass system was found noncytotoxic. However, quaternary glasses demonstrated negative affect on cell viability due to very high (7000 ppm) Na ion concentration. All the glasses investigated in current study are deemed fast degrading with further control over degradation rates, release kinetics desirable.