PbO B2O3 SiO2 Research Articles

An experimental and theoretical study to evaluate Al2O3–PbO–B2O3–SiO2–BaO radiation shielding properties

This study's objective is to evaluate an Al2O3–PbO–B2O3–SiO2–BaO glass system's radiation shielding characteristics. The composition of the glasses is 15Al2O3–25PbO–(60-x)B2O3–10SiO2–xBaO, with x in the 5–20 mol% range. Experimental results were used to determine the samples' linear attenuation coefficients (LAC), which were then confirmed by Phy-X program. Utilizing narrow beam transmission geometry, the experimental LAC values were determined. According to the results there was high agreement when comparing the theoretical and experimental values. The LAC values were used to calculate the prepared glasses' mass attenuation coefficients (MAC) and other relevant properties. The mean free path (MFP) values of the sample with 5 mol% BaO were 0.079, 2.549, 3.944 and 4.273 cm at 0.0595, 0.662, 1.173, and 1.332 MeV, thus demonstrating that raising the glass system's BaO enhances the prepared glasses' shielding capacity. According to radiation protection efficiency (RPE), the glasses' capacity to shield the photon is enhanced when their BaO content rises.

Physical, optical, mechanical and gamma ray shielding properties of Al2O3–PbO–B2O3–SiO2 glasses

Physical, optical, mechanical and gamma ray shielding properties of Al2O3–PbO–B2O3–SiO2 glasses

Correction: Spectroscopic features of Tl2O3 mixed multi-component Li2O–PbO–B2O3–SiO2–Bi2O3–V2O5 glass system

Correction: Spectroscopic features of Tl2O3 mixed multi-component Li2O–PbO–B2O3–SiO2–Bi2O3–V2O5 glass system

Spectroscopic features of Tl2O3 mixed multi-component Li2O–PbO–B2O3–SiO2–Bi2O3–V2O5 glass system

Spectroscopic features of Tl2O3 mixed multi-component Li2O–PbO–B2O3–SiO2–Bi2O3–V2O5 glass system

Investigation on PbO–B2O3–SiO2–RxOy Glasses Applied in Noncontact Silver Paste for Crystalline Silicon Solar Cells

Attempts to improve the application performance of noncontact silver (Ag) screen-printing paste for crystalline silicon solar cells, especially in terms of solderability, depend heavily on controlling the properties of the glass additive therein. Taking PbO–B2O3–SiO2–RxOy glasses as an example, this work demonstrates an improvement in the Ag paste due to the RxOy (e.g., ZnO, Bi2O3, Al2O3, and MgO) component. The RxOy components were found to help improve the sintering compactness of the Ag paste. The inclusion of the different RxOy components resulted in obvious differences in the soldering state of the sintered Ag grid. Microscopic observations revealed that the soldering state was related to the covering of the solder on the Ag grid and the growth rate of the intermetallic compound Ag3Sn during soldering. Comparatively, the sintered Ag grid was soldered more firmly when the glass containing the Bi2O3 or Al2O3 component was used in the Ag paste. This is due to the higher coverage of solder on these Ag grids and the appropriate growth rate of Ag3Sn. Considering these findings, the functions of the RxOy components are discussed comprehensively.

Energy-storage performance of PbO–B2O3–SiO2 added (Pb0.92Ba0.05La0.02)(Zr0.68Sn0.27Ti0.05)O3 antiferroelectric ceramics prepared by microwave sintering method

In this work, (Pb0.92Ba0.05La0.02)(Zr0.68Sn0.27Ti0.05)O3 (PBLZST) antiferroelectric (AFE) ceramics with the addition of PbO–B2O3–SiO2 raw glass powder as sintering aid were prepared via the microwave sintering method. The effects of glass content on the electrical properties and energy-storage performance of the ceramics were investigated in detail. With the glass content increasing, dielectric constant of the ceramics gradually decreased, while the breakdown strength increased. A maximum recoverable energy-storage density was about 2.3 J/cm3 and the corresponding efficiency was about 76.8 % to be achieved in the ceramics with 3-wt% glass at room temperature. The energy density of the PBLZST AFE ceramic with 3-wt% glass is 1.3 times as that (1.8 J/cm3) of the pure specimens. These results indicated that the energy-storage performance of AFE ceramics could be improved by adding proper glass and selecting novel sintering method.

Novel synthesis and optical characterization of phosphor-converted WLED employing Ce:YAG-doped glass

In this work, a novel environmentally friendly strategy toward phosphor-converted WLED employing Ce:YAG-doped glass via single-step low-temperature co-sintering technology was successfully synthesized, using low-cost PbO–B2O3–SiO2–ZnO glass as host, which showed good sintering behavior and high visible transparency under the sintering condition of 750 °C without noticeable interaction with phosphors. By simply changing thermal condition, phosphor doped concentration and specimen thickness for the viscous sintering of phosphor in glass (PiG), optical characterization of WLED can be easily tuned. As a result, it can be found that the ideal thermal condition is sintered at 700 °C for 40 min, the optimal amount of phosphor powder is controlled to be 5 wt% of the final mixture, and the best suitable thickness of specimens is 0.8 mm. The constructed PiG based WLED exhibits a high luminous efficiency of 134.33 lm/W, and a correlated color temperature of 4696 K as well as a color rendering index of 68.5. Enhanced thermal quenching property of PiG compared to phosphor with conventional silicone resin reveals the prominent feasibility of the present glass ceramic material in WLED application.

Properties of tellurite core/cladding glasses for magneto-optical fibers

The design and fabrication of a tellurite based magneto-optical (MO) glass for MO fiber applications are presented and discussed. Two MO glasses based on the TeO2–PbO–B2O3–SiO2 system were investigated in terms of thermal, optical and magnetic performances as a core/cladding pair for MO fiber fabrication. The optimal core and cladding elemental compositions were found to be: (58.8–60%) TeO2–(39.2–40%) PbO–(0.5–2%) B2O3mol% for core glass, and (76–58.2) TeO2–(36–38.8%) PbO–(0.5–2%) B2O3–(0.3–2%) SiO2mol% for cladding glass. The Verdet constant and Figure of merit of the fabricated glasses were measured under different wavelengths using a home-made optical bench.

The influence of In2O3 on electrical characteristics of iron mixed Li2O–PbO–B2O3–SiO2–Bi2O3 multi-component glass system

Glasses of the composition 19Li2O–20PbO–20B2O3–30SiO2–(10−x) Bi2O3–1Fe2O3: xIn2O3 with six values of x (0 to 5.0) were synthesized. Dielectric properties viz., dielectric constant, ε′(ω), loss, tanδ, ac conductivity, σac, electric modulus, M(ω) over wide ranges of frequency and temperature and also dielectric break down strength have been studied as a function of In2O3 concentration. The temperature dispersion of real part of dielectric constant, ε′(ω) has been analyzed using space charge polarization model. The dielectric loss (and also the electric moduli) variation with frequency and temperature exhibited relaxation effects and these effects were attributed to the divalent iron ion complexes. The ac conductivity exhibited maximal effect, whereas the activation energy for the conductivity demonstrated minimal magnitude at about 1.0mol% of In2O3. The conductivity mechanism is understood due to the polaronic transfer between Fe2+ and Fe3+ ions. The low temperature ac conductivity mechanism is explained following the quantum mechanical tunneling model. Spectroscopic studies viz., optical absorption and ESR spectra have revealed that the redox ratio (Fe2+/Fe3+) is maximal when the concentration of In2O3 is ~1.0mol%. The higher values of dielectric parameters observed at 1.0mol% of In2O3 are attributed to the presence of iron ions largely in divalent state and act as modifiers. The analysis of these results together with spectroscopic studies has indicated that when In2O3 is present in the glass matrix in higher concentrations (more than 1.0mol%) iron ions predominantly exist in trivalent state, occupy substitutional positions and make the glass more rigid. Such enhanced rigidity of the network is causing the decrease of dielectric parameters with the concentration of In2O3. Finally it is concluded that In2O3 mostly participate in the glass network in octahedral positions and make act as reducing agent (for iron ions) in the studied glass matrix when its concentration is ≤1.0mol%.

Optical and structural investigation of Dy3+–Nd3+ co-doped in magnesium lead borosilicate glasses

MgO–PbO–B2O3–SiO2–Nd2O3–Dy2O3 glasses are prepared by melt-quenching technique. The samples are characterized by X-ray diffraction (XRD), optical absorption, luminescence and Fourier transform infrared (FT-IR) spectral studied. XRD analysis evidently indicates that the prepared samples are fully amorphous nature. From the optical absorption spectra, the bonding environment surrounding the Dy3+ and their energy level scheme in glass network is analyzed. Enhancement of Dy3+ emission by non-radiative energy transfers from Nd3+ has been observed here. The samples emits intensive bluish yellow color from the 4F9/2→6H15/2, 6H13/2 transition of Dy3+ ions in these glasses which are nearer to white light and it is also supported by the chromaticity color coordinates. The FT-IR spectra reveal that network connectivity is increased with replacement of bonds B–O–B, Si–O–Si by more resistant B–O–Si bonds with gradually increasing the content of Dy3+ ions in the glass network. Along with spectroscopic parameters some physical parameters like density, refractive index etc. are measured for the glasses.

Application of the Barker lattice theory to modeling of thermodynamic properties of PbO–B2O3–SiO2 melts

The purpose of the present study was to apply the generalized lattice theory of the associated solutions to modeling of thermodynamic properties of melts in the PbO–B2O3–SiO2 system. Values of PbO activity used for simulation were obtained by the high temperature mass spectrometric Knudsen effusion method at the temperature 1100K for twenty-four compositions in the glass-forming region of the system studied. Thermodynamic data calculated for the PbO–B2O3–SiO2 melts were in agreement no worse than 40% with the experimental ones. In the frame of the model used the relative numbers of bonds of various types as a function of the melt composition were found when the second coordination sphere was taken into account. It allowed to discuss the concentration changes of Gibbs energy of formation in the melts considered in relation to the formation of various types of chemical bonds. Thermodynamic functions in PbO–B2O3–SiO2 melts found in the present study were compared also with the corresponding data calculated using the semi-empirical Kohler method using the data for the binary systems.

Optical and structural investigation of Eu3+ ions in Nd3+ co-doped magnesium lead borosilicate glasses

The Eu3+ ions doped MgO–PbO–B2O3–SiO2–Nd2O3 glasses have been prepared by melt-quenching technique. The optical and the structural characterizations are carried out for these glass samples. UV–Vis–NIR absorption spectra have prominent absorption bands in the Vis–NIR regions because of spectra materials Eu3+, Nd3+ ions in the glass network. Luminescence spectra are recorded with an excited wavelength of 355nm; the Eu3+ doped glasses have seven luminescence bands. The Judd–Ofelt intensity parameters, radiative transition probabilities and branching ratios are estimated for the observed Eu3+ luminescence bands in the spectra and compared with other literature data for Eu3+ in various compounds. The influence of Eu3+ ions on structure of the glass network has been studied by means of Fourier transform infrared (FT-IR) and Raman spectroscopy. The polymerization of the glass network takes place by the addition of Eu3+ ions due to the replacement of bonds B–O–B, Si–O–Si with more resistant B–O–Si, Si–O–Pb bonds. Along with spectroscopic parameters some physical parameters like density and refractive index are measured for these glasses.

Microstructure and energy-storage performance of PbO–B2O3–SiO2–ZnO glass added (Pb0.97La0.02)(Zr0.97Ti0.03)O3 antiferroelectric thick films

In this paper, Pb0.97La0.02(Zr0.97Ti0.03)O3 (PLZT 2/97/3) antiferroelectric (AFE) thick films with 0–5wt.% PbO–B2O3–SiO2–ZnO glass addition were successfully fabricated on alumina substrates via a screen printing method. The effects of the added glass on the microstructure, the dielectric properties, and the energy-storage performance of the PLZT 2/97/3 AFE thick films were investigated in detail. The results showed that the proper addition of glass powders was favor to form a denser microstructure with a pure perovsike phase. As a result, the dielectric properties and the energy-storage performance of AFE thick films were greatly improved by the addition of glass. The maximum recoverable energy-storage density of 3.1J/cm3 was obtained in 3-wt.% glass-added AFE thick films.

Microstructure and dielectric properties of glass/Al2O3 composites with various low softening point borosilicate glasses

The effects of various low softening point borosilicate glasses on both the sintering behavior and dielectric properties of glass/Al2O3 composites were investigated by FTIR, DSC, XRD, SEM and EDS. Results show that the addition of alkali oxides and PbO can decrease the glass softening temperature. While, the addition of Al2O3 and more SiO2 content in the glass can increase the continuity of glass network and further increase the glass softening temperature of samples. Glass with lower softening temperature has more time to flow to finish the densification of samples, and that can contribute to get better sintered composites. By contrast, CaO–PbO–B2O3–SiO2–Na2O–K2O glass/Al2O3 composites sintered at 875 °C for 15 min exhibit better properties of a bulk density of 3.06 g/cm3, a porosity of 0.17 %, a λ value of 2.47 W/m K, a er value of 8.05 and a tan δ value of 8.8 × 10−4 at 10 MHz.

Effect of Gamma‐Ray Irradiation on the Optical Properties of PbO–B2O3–SiO2 and Bi2O3–B2O3–SiO2 Glasses

Irradiation treatments on glasses in both PbO–B2O3–SiO2 and Bi2O3–B2O3–SiO2 systems were carried out under the 60Co γ‐ray radiation at a dose of 5.0 kGy. Ultraviolet and visible (UV–Vis) transmission spectra were used to compare the optical transmittance before and after irradiation in the wavelength range of 300–800 nm. The radiation‐induced absorption coefficient (RIAC), the optical mobility gap (E0), and the width of the energy tail above the gap (ΔE) were calculated by optical transmittance. The variation of these parameters indicated that the structure of glasses changed due to irradiation. The differences in the optical properties of the two glass systems were explained from the viewpoint of glass chemistry.

Microwave Dielectric Properties and Low‐Temperature Sintering of Cerium Oxide for LTCC Applications

The effect of glass additives on the microstructure, densification, and microwave dielectric properties of cerium oxide for low‐temperature co‐fired applications was investigated. Different weight percentages of quenched glass such as B2O3, B2O3–SiO2, Al2O3–SiO2, ZnO–B2O3, BaO–B2O3–SiO2, MgO–B2O3–SiO2, PbO–B2O3–SiO2, ZnO–B2O3–SiO2, 2MgO–Al2O3–5SiO2, LiO–B2O3–SiO2, Bi2O3–ZnO–B2O3–SiO2, and LiO–MgO–ZnO–B2O3–SiO2 were added to CeO2 powder. The crystal structure of the ceramic–glass composites was studied by X‐ray diffraction, microstructure by scanning electron microscopy, and phase composition using the energy‐dispersive X‐ray analysis technique. The microwave dielectric properties such as relative permittivity (ɛr), quality factor (Quxf), and coefficient of temperature variation of resonant frequency (τf) of the ceramics have been measured in the frequency range 4–6 GHz. Addition of B2O3 and Bi2O3–ZnO–B2O3–SiO2 lowered the sintering temperature of ceria to about 900°C. The 20 wt% B2O3 and 10 wt% Bi2O3–ZnO–B2O3–SiO2‐added CeO2 and sintered at 900° and 950°C showed: Quxf=24 200 and 12 000 GHz, ɛr= 13.2 and 22.4, and τf=−46 and –57.2 ppm/°C, respectively.

PbO–B2O3–SiO2 glass powders with spherical shape prepared by spray pyrolysis

PbO–B2O3–SiO2 glass powders were directly prepared using spray pyrolysis. The powders were spherical and fine-sized. One glass particle was obtained from one droplet by melting the precursors inside a hot wall tubular reactor. The characteristics of these powders were compared with those of the commercial product, which was prepared using the conventional melting process. The spherical powders, which were prepared using spray pyrolysis at 1000°C, had broad peaks at around 28° in the XRD spectrum. The glass phase was formed during the spray pyrolysis process even within a short residence time of the powders inside the hot wall tubular reactor. The mean size of the prepared glass powders was 1μm. The dielectric layers formed from the spherical, fine-sized glass powders had a high transparency at firing temperatures above 520°C. The maximum transparency of the dielectric layer formed from the glass powders obtained from spray pyrolysis was 95.3% at the firing temperature of 560°C. The dielectric layer formed from the spherical, fine-sized glass powders had a smooth surface and no void inside the dielectric layer.

Tailoring the Microwave Dielectric Properties of Ca5Ta2TiO12 Ceramics Through Glass Addition

Microwave dielectric properties of polycrystalline Ca5Ta2TiO12 ceramics have been tailored using different glass additives. Several glasses such as B2O3, SiO2, B2O3–SiO2, ZnO–B2O3, Al2O3–SiO2, Al2O3–B2O3–SiO2, BaO–B2O3–SiO2, MgO–B2O3–SiO2, ZnO–B2O3–SiO2, PbO–B2O3–SiO2, and 2MgO–Al2O3–5SiO2 were added to calcined Ca5Ta2TiO12 powder in different weight percentages. Among these glasses, addition of 0.1 wt% of SiO2, Al2O3–SiO2, Al2O3–B2O3–SiO2, MgO–B2O3–SiO2, and 2MgO–Al2O3–5SiO2 improved the microwave dielectric properties. Fluxing of Ca5Ta2TiO12 with 0.1 wt% of 2MgO–Al2O3–5SiO2 glass has ɛr=39, Qu×f>40 000 at 5 GHz and τf=+8 ppm/°C. Near‐zero τf was obtained with the addition of glasses like Al2O3–SiO2, Al2O3–B2O3–SiO2, MgO–B2O3–SiO2, and 2MgO–Al2O3–5SiO2. Addition of all the glasses except BaO–B2O3–SiO2 reduced the τf of Ca5Ta2TiO12 ceramics. Two weight percent glass addition to Ca5Ta2TiO12 ceramics reduced their sintering temperature down to 1450°C from 1625°C and τf close to zero but deteriorated the ɛr and unloaded quality factor. The effects of glass content on the structure and microstructure of Ca5Ta2TiO12 ceramics were studied by X‐ray diffraction and scanning electron microscopic techniques.

Thermal, Dielectric, and Optical Properties of Neodymium Borosilicate Glasses for Thick Films

Because of their thermal, dielectric, and optical properties, new glass compositions and thick‐filmed transparent dielectrics containing neodymium oxide (Nd2O3) were studied as a source of purer images in plasma display panels. In the present study, PbO–B2O3–SiO2 and PbO–B2O3–SiO2–ZnO–Al2O3 were used as starting glass compositions, to which up to 25 wt% of Nd2O3 then was added. Increased amounts of Nd2O3 increased the glass transition temperature and dielectric constant of the bulk glasses and decreased the coefficient of thermal expansion. The fired thick films (around 30 μm) allowed selectively visible light to penetrate and showed deep absorption properties at 585 nm that were related to an extraneous gas from neon discharge.

Single Phase Ba2Ti9O20 Microwave Dielectric Ceramics Prepared by Low Temperature Liquid Phase Sintering

Microwave dielectric ceramics of Ba2Ti9O20 were prepared by adding PbO–B2O3–SiO2 (PBS) as a liquid phase sintering aid. With the addition of 5 wt% PBS, dense and single-phase Ba2Ti9O20 dielectric resonators could be fabricated at a sintering temperature below 1200°C. The microwave dielectric properties of PBS–Ba2Ti9O20 ceramics were found to depend upon the density, the amount of liquid phase and the sintering temperature. Although glass addition results in a decrease of the dielectric properties, the sintered PBS–Ba2Ti9O20 ceramics still exhibit much better dielectric properties than that of pure Ba2Ti9O20 ceramics at low sintering temperatures.