Properties Of Lead Borate Glasses Research Articles

Impact of aluminum fluoride addition on crystallization, structure and thermal properties of lead borate glasses

The glass composition (70-x)PbO–(30-y)B2O3–(x+y)AlF3, where x and y ranges from 0 to 20 mol%, were prepared using the conventional melt-quenching-annealing technique. The structural and thermal properties of the glasses were comprehensively analyzed using techniques like Differential Thermal Analysis (DTA), Dilatometry, Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). XRD confirmed the amorphous, non-crystalline structure of the glasses. The glass network was found to be composed of structural units such as PbO4, BO4, BO3 and AlO6 using FTIR spectroscopy. FTIR analysis revealed significant structural changes, including the transformation of BO4 to BO3 units and the increase in non-bridging bonds, particularly with higher AlF3 content. DTA was instrumental in determining characteristic temperatures, such as the glass transition, melting, and peak crystallization temperatures, along with glass stability parameters (∆T, Hr, Tgr) for all samples. The study found that the addition of AlF3 led to a decrease in these characteristic temperatures when replacing B2O3, but an increase when replacing PbO. Variations in the density and thermal expansion of the lead borate glass were observed upon the addition of AlF3, decreasing when substituting for PbO and increasing when substituting for B2O3. These findings provide insights into the properties of oxyfluoride glasses, paving the way for future optimization in their composition for varied applications.

Effect of the addition of Al2O3, ZnO and TiO2 on the crystallization behavior, thermal and some physical properties of lead borate glasses

Effect of the addition of Al2O3, ZnO and TiO2 on the crystallization behavior, thermal and some physical properties of lead borate glasses

The Investigation of Lead Borate Glass Composites for Boron Neutron Capture Therapy Shielding

In this work, we studied the lead borate glass composites to optimize its shielding properties of thermal neutrons and gamma-rays for Boron Neutron Capture Therapy (BNCT) applications. Attenuation coefficients, half-value layer (HVL), and tenth-value layer (TVL) were measured for a broad range of gamma-ray energies, i.e., 356, 511, 662, 1173, 1274, and 1332 keV experimentally. Theoretical results using XCOM software show an agreement with the NaI(Tl) detector-based experimental measurements. The attenuation of collimated thermal neutrons, from Cf-252 source, was simulated using Monte Carlo-based code and compared experimentally with measurements by BF3 detector. A reasonable agreement between simulations and experiments was observed, suggesting that the shielding properties of lead borate glass (LBG) composites are monotonically increasing with the increasing of the lead and boron additives.

Mass stopping power and nuclear shielding behavior of lead borate glasses: Influence of gamma irradiation on physical properties

Four glassy systems with dissimilar PbO ratios were synthesized by the melting method. Raman scattering was used to study the chemical bonds inside the glass structures and follow the chemical changes occurring inside their networks after using the glasses in a radiation field. The glass samples are based on several tetrahedral and triangular groups where in BO3 is predominant. The energy gap of each sample was calculated from two different equations extracted from absorption and transmission measurements as ETauc and ETrans, respectively. Also, chemical durability has been studied to show the stability of these glasses against acidic environmental effect and followed by SEM images. Our findings showed that radiation effect on the prepared samples did not cause significant variations of structural and optical characteristics, however, increasing PbO concentrations resulting in enhancement of several radiation attenuation competencies. This study presented a comprehensive study of the radiation shielding properties of lead borate glass by assessing the effectiveness of proton, electron, neutron, and gamma shielding. Mass stopping power (ψp) and projected range (PR) values were calculated for proton particles (H1) using SRIM Monte Carlo simulation code and its subroutine TRIM, which predicts the radiation damage and atomic displacements per atom (dpa), while the ESTAR program was used to calculate ψe and the continuous slowing down approximation (CSDA) range for electrons. Furthermore; the findings estimate the excess lifetime cancer risk% for radiation workers behind the glass shields. Also, the glass with the lowest PbO content has the highest ΣR value, whereas the sample with the highest PbO content has the highest MAC value of gamma rays.

Direct influence of La on structure, optical and gamma-ray shielding properties of lead borate glasses

Lanthanum lead-borate glasses with chemical formula (50B2O3–10ZnO – (40-x)PbO) + x La2O3 wt% where (x = 0, 0.25, 0.5, 1, 1.75 and 2.5) have been prepared by the conventional melting method. FTIR measurements for the produced glasses in 4000–400 cm−1 and UV–vis spectra in 190–1100 nm wavelength have been carried out. Optical energy gap and index of refraction for the proposed glasses were evaluated using the absorbance spectrum fitting (ASF) and derivative absorbance spectrum fitting (DASF) models. In ASF method, the optical energy band gap was varied from 2.839 to 2.442 eV, while in DASF was from 2.851 to 2.777 eV for the indirect transition. The single-oscillator energy, dispersion energy parameter for all studied glasses were calculated. Indeed, molar refractivity (RM), molar polarizability (αM), reflection loss (RL), dielectric constant (ε), optical electronegativity (Δχ*), nonlinear optical susceptibility (χ(3)), and nonlinear refraction index (n2) have been determined. The capability of using the glasses as a promise radiation shielding was examined by calculating the mass attenuation coefficient by using WinXCOM and Phy-X/PSD programs within the photon energy (0.015–15 MeV). Attractive related shielding parameters such as; half value layer, effective atomic number, and mean free path along the considered photon energy range have been evaluated. Results were compared with some heavy metal oxide (HMO) and commercial glasses. Results reflected that the investigated glasses can be developed to be applied for photonics devices and protecting against exposure to ionizing radiation.

Influence of ZrO2 on gamma shielding properties of lead borate glasses

In this paper, new lead borate glass system in the chemical form of 40B2O3–40PbO–20Li2O3–xZrO2; where x = 0, 0.25, 0.50, 1, and 1.5 mol% has been synthesized. Gamma-ray shielding properties of these glasses have been tested in terms of mass attenuation coefficient (μ/ρ), half value layer (HVL), effective atomic number (Zeff), mean free path (MFP), and exposure build-up factor (EBF). The μ/ρ values of the prepared glasses were generated by FLUKA Monte Carlo simulations over an extended energy range of 0.015–15 MeV, and then, the generated data were verified using the calculated values of XCOM software. The results showed that gamma-ray shielding ability of BPLZ0.00 is superior among the other prepared glasses. Moreover, the gamma-ray shielding properties of the current glass system have been compared with that of some commercial glasses and newly developed HMO glasses. It can be concluded that the prepared glass system could be useful to design and/or develop novel shields for radiation protection applications.

The influence of Ba2+ and Sr2+ ions with the Dy3+ ions on the optical properties of lead borate glasses: experimental and Judd–Ofelt comparative study

Two glasses compositions (50B2O3–30PbO–20SrO–xDy) and (50B2O3–30PbO–20BaO–xDy) where x=0.0.5%, and 1.0% in wt.% ratio were prepared using melt quenching technique in order to investigate the effect of Ba2+ and Sr2+ ions in Dy3+ ions doped lead borate glass. The optical properties such as bandgap and the refractive index distribution were examined using UV–vis-NIR absorption spectroscopy. The FTIR absorption spectra of all prepared samples were similar except for the metallic bands in the fingerprint region. The obtained experimental data were compared with theoretical data calculated by Judd–Ofelt framework. The Judd–Ofelt parameters Ωλ (λ=2, 4 and 6) were calculated and the trend was Ω2<Ω4<Ω6 which is the common trend. The experimental oscillator strength (fexp), the calculated oscillator strength (fcal), the estimated refractive indexes (n) at each transition, the lifetime of radiative transitions (τ), the branching ratio (β), the absorption cross-section (σabs(λ)) and the emission cross-section (σemis(λ)) were also estimated and discussed. The optical gain coefficient (G(λ)) was calculated not only for the most intense emission transition but also other emission peaks. The obtained results indicated that the prepared samples are promising materials for laser emission and optical communication applications.

Optical and Electrical Properties of Lead Borate Glasses

Lead borate glass matrix of composition (x PbO-10 ZnO-(90 − x) B2O3), (x = 50–90 wt.%) was prepared by the melt quenching technique. The amorphous nature of these glasses was confirmed via x-ray diffraction (XRD) measurements. Both infrared spectra (400–4000 cm−1) and UV–visible absorption 200–1100 nm have been measured for all prepared samples in order to study the optical properties of samples. We found that the optical energy gap ( $$ E_{\rm{gap}}^{\rm{optical}} $$ ) decreased, however, Urbach’s energy (EU) increased with increasing PbO content. By using UV–visible absorption, electrical conductivity ( $$ \sigma_{\rm{electrical}} $$ ), optical conductivity ( $$ \sigma_{\rm{optical}} $$ ), refractive index (n), extinction coefficient (k), optical complex dielectric constant (e), surface and volume energy loss functions (SELF and VELF) have been calculated. In addition to optical basicity (Λth), optical basicity on the basis of optical band gap ( $$ \varLambda_{{E_{\rm{gap}} }} $$ ), and electronic polarizability on the basis of optical band gap ( $$ \alpha E_{\rm{gap}}^{\rm{optical}} $$ ) have been calculated. Dielectric parameters (e′ and e″) and ac conductivity (σac) have been carried out in (100 Hz–100 kHz).

Lead borate glasses triply doped with Dy3+/Tb3+/Eu3+ ions for white emission

Fully amorphous lead borate glasses triply doped with Dy3+/Tb3+/Eu3+ were synthesized and next studied using optical spectroscopy. The characteristic luminescence bands originating to electronic transitions of Dy3+/Tb3+/Eu3+ ions were observed under direct excitation of Dy3+. Moreover, the influence of concentration of rare earth ions on spectroscopic properties of lead borate glasses was examined. The obtained experimental results indicate that energy transfer between these rare earth ions is possible. From the emission spectra, the Commission Internationale de I'Eclairage (CIE) chromaticity coordinates (x, y) are calculated in relation to potential application lead borate glasses for white light emitting devices. It has been proved that our glass systems exhibit warm white emission originating from the simultaneous generation of several bands of Dy3+, Tb3+, Eu3+ under the UV–visible light excitation.

Structural, Electrical and Thermal Properties of Lead Borate Glass Doped by V2O5 Content

Structural, Electrical and Thermal Properties of Lead Borate Glass Doped by V2O5 Content

On the mechanical properties of lead borate glass

The mechanical properties of lead borate glasses were investigated using ultrasonic wave velocity measurement and nanoindentation. Creep tests at room temperature were performed by holding the indenter at peak load for extended time. Both Young's modulus and nanohardness decreased with increasing PbO molar fraction from 0.35 to 0.75. Creep decreased by increasing PbO from 0.35 to 0.50 mole fraction, and remained relatively unchanged at greater lead concentrations. The variation of Young's modulus with composition was attributed primarily to that of boron coordination number, whereas the variation of creep was attributed to the evolution of lead from glass modifier to former with the increase of lead concentration. Furthermore, the Young's moduli of glasses were predicted using Makishima–Mackenzie model. By considering the effect of cations' coordination numbers on the properties of oxides, marked improvement in the predictions of Young's modulus were made over previous such estimations.

Devitrification properties of lead borate glasses

Lead borate glasses containing 30 to 60 mol% PbO were prepared by melt quenching technique and devitrified by long duration heat treament in the supercooled region. Glasses crystallized on heating above their glass transition temperature, and the crystalline phases produced on devitrification were characterized by XRD and DSC analyses. Glass with 30 mol% PbO slowly formed a solid solution of Pb6B10O21 and Pb5B8O17 crystalline phases, while glasses with 40 and 50 mol% PbO formed a mixture of Pb6B10O21, Pb5B8O17 and the remanent glassy phase. Glasses with higher PbO concentration of 56 to 60 mol% devitrified completely and produced only Pb5B8O17 crystalline phase. Lead borate glasses with PbO concentration of 40 to 50 mol% showed maximum thermal stability against devitrification, the ease of crystallization of glasses was correlated with the fraction of tetrahedral borons in them.

Fast Neutron Irradiation Effect on Some Optical Properties of Lead Borate Glass Doped with Samarium Oxide

Fast Neutron Irradiation Effect on Some Optical Properties of Lead Borate Glass Doped with Samarium Oxide

Fluoride-modified electrical properties of lead borate glasses and electrochemically induced crystallization in the glassy state

Lead fluoroborate glasses were prepared by the melt-quenching technique and characterized in terms of (micro)structural and electrical properties. The study was conducted on as prepared as well as temperature- and/or electric field–treated glass samples. The results show that, in the as-prepared glassy-state materials, electrical conductivity improved with increasing the PbF2 glass content. This result involves both an increase of the fluoride charge carrier density and, especially, a decrease of the activation energy from a glass structure expansion improving charge carrier mobility. Moreover, for the electric field–treated glass samples, surface crystallization was observed even below the glass transition temperature. As previously proposed in literature, and shown here, the occurrence of this phenomenon arose from an electrochemically induced redox reaction at the electrodes, followed by crystallite nucleation. Once nucleated, growth of β-PbF2 crystallites, with the indication of incorporating reduced lead ions (Pb+), was both (micro)structurally and electrically detectable and analyzed. The overall crystallization-associated features observed here adapt well with the floppy-rigid model that has been proposed to further complete the original continuous-random-network model by Zachariasen for closely addressing not only glasses’ structure but also crystallization mechanism. Finally, the crystallization-modified kinetic picture of the glasses’ electrical properties, through application of polarization/depolarization measurements originally combined with impedance spectroscopy, was extensively explored.

Influence of compositions on sealing temperature and properties of lead borate non-crystallizing sealing glasses

Lead borate sealing glasses, composed of 30–75PbO, 20–65B 2O 3, 0–10ZnO, 1–5Bi 2O 3 and 0–4GeO 2 in mole percent, were prepared by conventional melting-quenching method. Influence of PbO/B 2O 3 ratios and the content of oxide additives on sealing temperature, thermal expansion properties, thermal stabilities and mechanical properties of lead borate glass were investigated by IR, DSC, thermal expansion and mechanical measurement. Results indicate that the ratio of PbO/B 2O 3, both as the main glass formers, had crucial influence on network structure of lead borate glass. An appropriate proportion of PbO/B 2O 3, ZnO and GeO 2 are beneficial to lower sealing temperature and stabilize the glass against devitrification. When 1 mol% GeO 2 is introduced, the glass possesses the highest stability and lowest sealing temperature (400 °C), which is desirable for low-temperature sealing. Bi 2O 3 has little effects on the melting temperature and sealing temperature, while it helps to improve mechanical properties of lead borate glasses. Only the introduction of GeO 2 causes a little tendency for crystallization. The modified Johnson–Mehl–Avrami (JMA) equation was used to describe the crystallization kinetics of GeO 2 doped lead borate glasses. The precipitation of crystals before melting is a block for the decrease of sealing temperature. Furthermore the adjustability of the coefficient of thermal expansion caused by the additives would expand applications of lead borate glass.

Some physical properties of lead borate glasses. II. A compensation model for the transition region

Deals with the transition-temperature region (TR) in the DC electrical resistivity ( rho )-temperature (T) dependence of lead borate glasses with PbO content up to 24 mol.%. The temperature dependence of ln mod (1/ rho c) delta rho / delta T mod , where rho c is the resistivity at the critical temperature, is characterised by: (i) two straight lines with an intersection at a certain compensation point, in the case of untempered samples and samples tempered at 340 degrees C; (ii) three straight lines with a common intersection point, for samples tempered within the range 380-460 degrees C. These results are attributed to the compensation effect due to the entropy fluctuations in the mean electron density and the polarisation at the interface between the metastable microphases. Mathematical relations have been derived for rho (T) in both cases. A reasonable fit is obtained between the theoretical and experimental plots of rho (T) in the TR.

Some physical properties of lead borate glasses. I. Influences of heat treatment and PbO content

Lead borate glasses (LBG) of composition (x)PbO:(100-x)B2O3 with x=8, 12, 14, 16, 20 and 24 mol.% have been prepared. The structural analysis of the prepared samples was carried out using X-ray diffraction, differential thermal analysis (DTA) and infrared spectroscopy (IR). The X-ray diffraction results revealed that the amount of crystalline phase present was <5%. Two exothermal peaks, due to crystallisation, appeared at around 669 and 860 K in the DTA curves of LBG containing 20 mol.% PbO. The IR analysis indicated that both ionic and covalent bonding of lead ions are probable; the broad absorption band around 3400 cm-1 was assigned to O-H stretching. The effects of heat treatment and PbO content on the microhardness (Hv) and DC electrical resistivity ( rho ) were investigated. The observed increase in Hv with increasing PbO content was attributed to the compacting role of Pb in the glass structure. The temperature (T) range for measuring rho was 353-583 K. The reciprocal temperature dependence of log rho was classified into three regions. In the low-temperature region, 416-434 K, the conduction was of ionic type with protons as charge carriers and an Arrhenius relation controls the rho (T) dependence. The transition region, 434-487 K, is explained physically and mathematically by a new model in a subsequent paper. In the high-temperature region (HTR), 487-583 K, the ionic conduction proceeded and the Arrhenius equation was fulfilled. In this region oxygen ions were the charge carriers for glasses containing <or=12 mol.% PbO, and lead ions were the charge carriers for higher PbO contents. The activation energy in the HTR decreased as the tempering temperature increased, which was attributed to the coalescence of the microclusters of the dispersed phase due to the heat treatment.