Na2O BaO Research Articles

Accelerating densification of the terminal electrode with improved adhesion by sodium ions doping for MLCC copper paste

Glass frits effectively facilitate the sintering densification to produce high-density terminal electrodes, crucial for achieving high reliability of MLCC (Multilayer Ceramic Capacitors) devices. However, manufacturing terminal electrodes with high density and strong adhesion under low-temperature sintering condition still has enormous challenges. Herein, Na2O–BaO–ZnO–B2O3–SiO2 glass has been fabricated for low temperature sintering copper paste. We demonstrate that the densification degree and adhesion strength of the terminal electrode can be notably optimized by adjusting the Na2O content in the glass frit. The doping of Na+ in glass effectively improves the wettability of the melt on the copper substrate and the surface tension of the glass melt, enhancing the capillary force in the liquid phase sintering process. The rate of electrode densification is accelerated by the increase in capillary force, thus reducing the sheet resistance of copper film from 4.52 to 4.30 mΩ/□. Furthermore, with the increase in the Na+ content, the work of adhesion between glass and ceramic gradually increases, which effectively enhances the shear strength of the electrode from 19.66 MPa to 29.55 MPa. Our work provides novel insights for the design of glass compositions in the field of terminal paste.

Y2O3 reinforced B2O3–SiO2–BaO–Na2O glass system: A characterization study through physical, optical and gamma / neutron shields characteristics

Glasses with the composition 48B2O3– 13SiO2– 7BaO- (32-x) Na2O-xY2O3, (x = 0, 1, 2, 4, and 8 mol %) were synthesized by the melt quenching procedure. There is good transparency in every glass sample. The increase in density (2.825–3.894 gm/cm3) of the present glasses is what triggered the decline in molar volume (25.41–21.80 cm3/mol) and the decrease in the Boron–Boron distance (0.475–0.452 nm). The estimated values show that Eopt.indi. &Eopt.di are 2.317, 2.672, 2.8, 2.98 and 3.1 eV, 2.69, 2.92, 3.05, 3.25, and 3.44 eV respectively, whereas (Eu) values declined. As the Y2O3 increased the refractive index (nD) increased. (nD) of the synthesized glasses using Eopt.indi.&Eopt.di were estimated. To find the radiation properties of the suggested glasses, the Phy-X/PSD code was employed. We concluded that the current glasses have better radiation shielding capabilities when employed in such fields. As the Y2O3 replacing ratio increased ∑R increased.

Fabrication and characterization of TeO2–Na2O–BaO glass doped with Yb2O3 for optical and particulate-radiation shielding applications: Role of Bi2O3/WO3

In this research, transparent 64TeO2–15Na2O–5BaO-(10-x)Bi2O3-(x+5)WO3-1Yb2O3 glasses were prepared and analysed for their optical, structural, and radiation protection potentials. Samples of the novel glasses were produced in the laboratory, starting with the melting-quenching process. The glasses were characterised using standard laboratory procedures and dedicated software. The influence of replacing WO3 with Bi2O3 on the investigated properties was highlighted. The values of the glass density increase from 5.42 g/cm3 to 5.67 g/cm3 as the bismuth oxide concentration increases from 0 to 10 mol%. XRD spectrograms of the glass samples reveal that they have an amorphous structure. The glasses had high optical transparency, which was reduced when WO3 was replaced by Bi. The photoluminescence decay showed that the luminescence lifetime of Yb3+ decreases with increasing bismuth concentration. For electrons, the mass stopping powers (Sp) were within 1.253–8.918 MeV cm2/g, 1.241–8.721 MeV cm2/g, and 1.232–8.549 MeV cm2/g for samples containing 0, 5, and 10 mol% of Bi2O3. Generally, Sp of electrons, protons, alpha particles, and 12C ions were in the order, (Sp)TWBi−0>(Sp)TWBi−5>(Sp)TWBi−10. Increasing the concentration of Bi atomic density in the glasses improved the total interaction probability of thermal neutrons but reduced the ability of the glasses to moderate fast neutrons.

Reinforced dielectric properties and energy storage performance of BaO–Na2O–Nb2O5–SiO2–TiO2–ZrO2 dielectric glass ceramics

Glass ceramic capacitors with ultra-fast discharge speed and high energy density play a key role in pulse power systems. However, the low dielectric performance of glass ceramics limits their energy storage density. To reinforce the dielectric properties and energy storage capacity of glass ceramics, the microstructures and contents of the ceramic phases composing BaO–Na2O–Nb2O5–SiO2–TiO2–ZrO2 glass ceramics can be effectively controlled by adjusting different crystallization conditions. At the optimum crystallization temperature of 950 °C, the maximal theoretical energy storage density of BaO–Na2O–Nb2O5–SiO2–TiO2–ZrO2 dielectric glass ceramics reaches 9.54 J/cm3 at 1394 kV/cm, which is 1.47 times that of dielectric glass ceramics crystallized at 750 °C. Moreover, glass ceramics exhibit a rapid discharge rate of approximately 0.237 μs and superior power density (2.39 MW/cm3) at 800 kV/cm. Significant enhancement in energy storage performance of the above ceramics is attributed to the component regulation and the reduction of interface polarization.

Synthesis and Characterization of La2O3–BaO–Na2O–SiO2–Bi2O3 Glass as a Potent Shield Against Ionizing Radiation

In recent years, the scientific community has spent significant effort exploring radiation-shielding glass materials. The present work was conducted by synthesizing a glass series of 20La2O–10BaO –15Na2O–(55−x)SiO2–xBi2O3, x: 0, 5, 15, and 25 wt%. After producing the samples, in-depth studies were performed on the physical, optical, thermal, and radiation attenuation properties of the fabricated glass series. A radical color change from nearly neutral to dark-brown color occurred as Bi2O3 entered the glass network. The density values equaled 2.8324, 2.9511, 3.0992, and 3.3657 g cm−3 for LBSS1 to LBSS4 samples, respectively. According to XRD patterns, neither sharp nor moderate peaks developed; a hump-like formation between 20 and 35 degrees was visible in all glass samples. FTIR measurement revealed transmission as a function of varying wavenumber from 4000 to 400 cm−1 for the prepared glass specimens, and different bond types were noted. The UV–Vis technique removes it displayed that increasing Bi2O3 content blocked light transmission throughout the glass medium. The radiation-shielding parameters of linear attenuation coefficient (LAC), mass attenuation coefficient, transmission factor, and half value layer were calculated with experimental and MC simulation methods for all glass samples at six different energies between 356 and 1332 keV. The results were compared with the Phy-X database, and good agreement was obtained. The highest LACs were obtained at the lowest energy (356 keV) with values of 0.3108, 0.3455, 0.4471, and 0.5486 cm−1 for LBSS1, LBSS2, LBSS3, and LBSS4 glasses, respectively. The photon attenuation ability of the LBSS glasses increased by increasing the Bi2O3 ratio, especially at low energies. Therefore, the authors can conclude that future applications, such as observation window in CT rooms, may efficiently exploit LBBS4 glass system.

КРИСТАЛЛИЗАЦИЯ СТЕКОЛ В РАЗРЕЗЕ Nа2O·2B2O3 — BaO·2B2O3 НАТРИЕВО-БАРИЕВО-БОРАТНОЙ СИСТЕМЫ

The results of crystallization of glass powders of the diborate section of the Na2O BaO B2O3 system are presented. The glass transition temperatures and temperature regions of crystallization at a heating rate of 10 K/min were determined by DTA and XRD methods; the formed crystalline phases were identified, and the nature and temperatures of their melting were established. It is shown that the section under study is not a pseudobinary system, but only a partial section of the sodium-barium borate system. It is shown that the Na2O·2BaO·9B2O3 compound is the phase of primary crystallization in the section; its field covers the majority of the section. The second known ternary compound, Na2O·2BaO·5B2O3, apparently melts peritectically. It has been established that during long-term heat treatment of glasses in a monolithic state, a new phase is formed in them with an approximate composition of Na2O·2BaO·6B2O3.

Dielectric and energy storage properties of Ba0.85Ca0.15Zr0.1Ti0.90O3 ceramics with BaO–Na2O–Nb2O5–WO3–P2O5 glass addition

Dielectric and energy storage properties of Ba0.85Ca0.15Zr0.1Ti0.90O3 ceramics with BaO–Na2O–Nb2O5–WO3–P2O5 glass addition

High gas tightness ZrO2-added silicate glass sealant with low thermal stress for solid oxide fuel cells

A low leakage rate sealant of 10 wt% ZrO2-added CaO–K2O–Na2O–BaO silicate glass for SOFC has been studied. The structure of the sealant is stable at high temperatures with leakage rates less than 10−4 sccm∙cm−1, and no crystal except for ZrO2 is found in XRD analysis after heating at 800 °C for 100 h. ZrO2 is distributed in the glass matrix and plays a supporting role in avoiding over-softening at operating temperature. Good compatibility in both oxidizing and reducing atmospheres between the sealant and SUS430 interconnect was proved by SEM at 750 °C for 100 h. A fully coupled 3D Multiphysics button SOFC is constructed for mechanical analyses. The results show that the increase of ZrO2 in the sealant will decrease the stress and displacement in the SOFC. Besides, the width of the sealant also affects the stress value and distribution. The results show that GZ10 is a competitive sealing material compared with other ZrO2-added sealants.

Effects of Al2O3 addition on sintering behaviour, microstructure, and physical properties of Al2O3/vitrified bond CBN composite

The effects of Al2O3 content on the sintering behaviour, microstructure, and physical properties of Al2O3/vitrified bonds (SiO2–Al2O3–B2O3–BaO–Na2O–Li2O–ZnO–MgO) and Al2O3/vitrified bond cubic boron nitride (CBN) composites were systematically investigated using X-ray diffraction, differential scanning calorimetry, dilatometry, scanning electron microscopy, and X-ray photoelectron spectroscopy. Various amounts of Al2O3 promoted the formation of BaAl2Si2O8 and γ-LiAlSi2O6, increasing the relative crystallinity of the Al2O3/vitrified composite from 85.0 to 93.2%, resulting in residual compressive stress on BaAl2Si2O8, thereby influencing the thermal behaviour and mechanical properties of the Al2O3/vitrified composite. The bulk density, porosity, flexural strength, hardness, and thermal conductivity of 57.5 wt% Al2O3 sintered at 950 °C were 3.12 g/cm3, 6.1%, 169 MPa, 90.5 HRC, and 4.17 W/(m·K), respectively. The coefficient of thermal expansion of the bonding material was 3.83 × 10−6 °C−1, which was comparable to that of CBN, and the number of N–Al bonds were increased, which boosted the flexural strength of the Al2O3/vitrified CBN composite to 81 MPa. The excellent mechanical properties, compact structure, and suitable interfacial bonding state with the CBN grains of the Al2O3/vitrified composite make it a promising high-performance bonding material for superhard abrasive tools.

Crystallization temperature dependence of structure, electrical and energy storage properties in BaO–Na2O–Nb2O5–Al2O3–B2O3 glass ceramics

For dielectric capacitors, high energy density and discharge power density are crucial for utilisation in pulsed power devices. In this paper, BaO–Na2O–Nb2O5–Al2O3–B2O3 (BNN-AB) glass ceramics were successfully fabricated by melt quenching and heat treatment techniques. With increasing crystallization temperature, both the dielectric permittivity and breakdown strength (BDS) first increased and then decreased. When the crystallization temperature was lower than 800 °C, the principal crystalline phase was Ba2NaNb5O15 and the secondary phase was NaNbO3. When crystallization temperature was increased from 800 °C to 830 °C, a small amount of a third phase (Al4B2O9) appeared. At the crystallization temperature of 770 °C, the compact glass ceramics with a fine grain structure had the highest permittivity (∼216 @ 25 °C) and high BDS (∼1170 kV/cm). A single-layer capacitor made of glass ceramics had a high power density (∼414 MW/cm3) and discharge energy density (∼1.93 J/cm3), measured by the charge-discharge test platform under the applied field strength of 500 kV/cm. The discharge energy density of glass ceramics sample was as much as 7.7 times that of the mother glass. The above evidences indicate that BNN-AB glass ceramic materials have broad application prospects in the field of dielectric energy storage.

Optical and structural properties of Eu3+ doped MgO–Li2O–Na2O–BaO–B2O3 glasses for scintillating glass applications

The glass systems with composition of 17MgO–10Li2O-(57-X) B2O3–6BaO–10Na2O-XEu2O3 (X = 0.0(BMLNBa), 0.1(BMLNBaEu0.1), 0.3(BMLNBaEu0.3), 0.5(BMLNBaEu0.5) and 1.0(BMLNBaEu1.0) mol% were prepared and studied their optical, structural properties for scintillating applications. Density and refractive index of the glasses increases with increase in Eu2O3 content indicating close packing of glass network. IR spectra reveal signature peaks of the borate network. Photoluminescence spectra of glass systems reveals emission bands which corresponds to 5D0 →7F0 (579 nm), 5D0 →7F1 (590 nm), 5D0→7F2 (615 nm), 5D0 →7F3 (654 nm), 5D0→7F4 (700 nm) transitions. The emission and excitation intensity depends on Eu3+ ions where emission wavelength was observed at 615 nm and excited wavelength at 394 nm. The highest emission intensity was observed for BMLNBaEu0.3 glass. Asymmetry ratio (IR/O) is calculated and compared with other glasses. The phonon side-band spectra are used to calculate phonon energy of the present glass system. Judd-Ofelt analysis and radiative properties have been evaluated for BMLNBaEu0.3 glass and compared with other glass compositions. Using phonon energy, the coupling strength ‘g’, host dependent parameters (α) and multi-phonon relaxation rates (WMPR/Wo) have been evaluated. Phonon coupling strength shows 0.0054, 0.0108 and 0.0546 for BMLNBaEu0.3, BMLNBaEu0.5 and BMLNBaEu1.0 glasses respectively. The results obtained indicate the glasses are potential candidates for the scintillating material applications.

Influence of Na2O on the thermodynamics properties, viscosity, and structure of CaO–SiO2–MgO–Al2O3–BaO–Na2O slag

This article investigated the effect of Na2O on the viscosity and structure of CaO–SiO2–MgO–Al2O3–BaO–Na2O slag. To understand the stability of slag at high temperatures, the “excessive heat of slag” was calculated. The structure of slag was analyzed using Raman and 27Al magic angular spinning nuclear magnetic resonance (MAS-NMR) techniques. The results showed that the viscosity decreased with an increase in Na2O content in the range of 0 to 4 wt%, while the excessive heat of slag increased because the effect of slag composition on its heat capacity was more significant than that of temperature. From the perspective of heat supply, it should increase the fuel ratio of the blast furnace to ensure a stable furnace temperature when raising Na2O content. The mole fraction of Q Si0 (QSin, n is the number of bridging oxygen in a [SiO4]-tetrahedron) and Q Si2 increased gradually, whereas that of Q Si3 decreased obviously. The [SiO4]-tetrahedral structures were depolymerized, which reduced the number of bridging oxygen. Simultaneously, the increment in non-bridging oxygen caused the transformation from AlO4 to AlO5 and AlO6, thus decreasing the fraction of the network former (AlO4). The connection between [SiO4] and AlO5 or AlO6 weakened the strength of the network structure and increased the proportion of the Al–O bond.

Structural, dielectric and energy storage properties of BaO–Na2O–Nb2O5–P2O5 glass-ceramics

A series of (1−x)[(2BaO–0·5Na2O)–1P2O5] –xNb2O5 (BNPN, x=0·41, 0·43, 0·45, 0·48) glass-ceramics based on phosphate glasses have been prepared via a controlled-crystallisation route. The structure, dielectric properties, interfacial polarisation and energy storage properties were systematically investigated. The x-ray diffraction results showed the simultaneous presence of Ba2NaNb5O15 tungsten bronze structure (TTB) and the NaNbO3 perovskite. A stable dielectric constant over a temperature range from 25–200°C, low dielectric losses less than 0·03 and excellent frequency stability at room temperature were obtained. The decrease of niobium content promoted the TTB crystallisation with improvement of the high dielectric properties of the system. The optimum of the dielectric constant and recoverable energy storage density were obtained for BNP41 crystallised at 1000°C. Analyses of the complex impedance indicated that the niobium content and crystallisation temperature affect the interfacial polarisation.

Investigation of the effect of using radiation protective glasses on the photon fluence-to-dose conversion coefficients of eye substructures

The use of radiation protective glasses is common in radiation-contaminated environments. However, the effect of these glasses has not yet been investigated on the fluence-to-dose conversion coefficients (DCCs). The aim of this study is to investigate the effect of five types of gamma ray protective glasses on the photon fluence-to-DCCs of different eye substructures. For this purpose, a real eye model has been used and its conversion coefficients have been calculated in the presence of five types eye protective glasses with chemical formulae of ZnO–PbO–B2O3, Bi2O3–PbO–B2O3, PbO–B2O3, PbO–BaO–Na2O–MgO–B2O3 and BaO–Nb2O3–P2O5. Calculations were performed for monoenergetic photon sources, whose energy ranges from 0.02 to 10 MeV, with different polar and azimuthal angles. The results indicate that the use of radiation protective glasses has acceptable effects on reducing the fluence-to-DCCs only at low photon energies up to 500 keV. At medium energy levels up to about 1 MeV, the effect of the glasses is negligible. However, at high energies it increases the fluence-to-DCCs for sensitive parts of the eye.

Feldspar-based CaO–K2O–Na2O–BaO silicate glass sealant for solid oxide fuel cells

Sealants have been widely used in solid oxide fuel cells (SOFCs), and glass sealants have shown considerable potentials due to their low leakage rate. We report a type of feldspar-based glass sealant, mainly composed of CaO–K2O–Na2O–BaO, with a coefficient of thermal expansion (CTE) of 10.11 × 10−6 k−1, a glass transition temperature at 528 °C, and a softening temperature at 573 °C. Using this sealant to seal anode-supported SOFCs, the open-circuit voltage (OCV) remains at 1.08 V after five thermal cycles and 50-h aging at 750 °C, close to the theoretical OCV value. The SEM and EDS reveal stable interface between the glass sealant and the anode, indicating excellent performance of the CaO–K2O–Na2O–BaO glass sealant for SOFC sealing applications.

Achieving Superior Energy Storage Properties and Ultrafast Discharge Speed in Environment-Friendly Niobate-Based Glass Ceramics.

Glass ceramics composed of Na2O-BaO-Bi2O3-Nb2O5-Al2O3-SiO2 (NBBN-AS) were modified by rare-earth doping and prepared via the melt-quenching process accompanied by controlled crystallization. High-resolution transmission electron microscopy displayed the glassy matrix closely encompassing the nanosized NaNbO3, Ba2NaNb5O15, BaAl2Si2O8, and AlNbO4 crystalline grains. With rare-earth doping, the NBBN-AS glass ceramics' theoretical energy storage density can reach 22.48 J/cm3. This excellent energy storage property is credited with increasing breakdown strength, and numerical simulation was applied to reveal the intrinsic mechanism for increased breakdown strength by rare-earth doping. The charge-discharge results indicated a giant power density of 220 MW/cm3 as well as an ultrafast discharge speed of 11 ns. The results indicate that the glass ceramic can be used in advanced capacitor applications.

Comparative study of two bismuth–borate glasses in terms of gamma shielding parameters at medical diagnostic energies and neutron shielding characteristics

Gamma shielding parameters for Bi2O3–B2O3 and Bi2O3–BaO–Na2O–MgO–B2O3 glasses have been investigated at medical diagnostic energies (20, 30, 40 and 60 keV). Mass attenuation coefficients calculated using the FLUKA code and XCOM program have been shown to be in very good agreement with each other. The evaluated parameters have indicated that the gamma shielding performance, at a specific energy, of each of the glass systems increases with the increment of Bi2O3. At 20 and 30 keV (40 and 60 keV), 55Bi2O3–45B2O3 (40Bi2O3–20BaO–10Na2O–10MgO–20B2O3) sample exhibits the best gamma shielding performance. At 40 and 60 keV, mass attenuation coefficients of all the glass samples are comparable to that of lead. Furthermore, both of the glass systems exhibit better shielding characteristics than the ordinary concrete. Finally, calculations of the macroscopic removal cross-sections of the glass systems have shown that 45Bi2O3–55B2O3, among all the samples, has the best shielding ability against fast neutrons.

Investigation of photon, neutron and proton shielding features of H3BO3–ZnO–Na2O–BaO glass system

The current study aims to explore the shielding properties of multi-component borate-based glass series. Seven glass-samples with composition of (80-y)H3BO3–10ZnO–10Na2O–yBaO where (y = 0, 5, 10, 15, 20, 25 and 30 mol.%) were synthesized by melt-quench method. Various shielding features for photons, neutrons, and protons were determined for all prepared samples. XCOM, Phy-X program, and SRIM code were performed to determine and explain several shielding properties such as equivalent atomic number, exposure build-up factor, specific gamma-ray constants, effective removal cross-section (ΣR), neutron scattering and absorption, Mass Stopping Power (MSP) and projected range. The energy ranges for photons and protons were 0.015–15 MeV and 0.01–10 MeV, respectively. The mass attenuation coefficient (μ/ρ) was also determined experimentally by utilizing two radioactive sources (166Ho and 137Cs). Consistent results were obtained between experimental and XCOM values in determining μ/ρ of the new glasses. The addition of BaO to the glass matrix led to enhance the μ/ρ and specific gamma-ray constants of glasses. Whereas the remarkable reductions in ΣR, MSP, and projected range values were reported with increasing BaO concentrations. The acquired results nominate the use of these glasses in different radiation shielding purposes.

Experimental studies on the gamma photons-shielding competence of TeO2–PbO–BaO–Na2O–B2O3 glasses

In this work, glass composed of (40 + x) PbO–5 TeO2–15 BaO–(20 − x) Na2O–20 B2O3 (x = 0, 5, 10, 15, and 20 mol%) was prepared via melt-quenching and the gamma-shielding competency was studied. The results showed that the density and molecular weight increased from 5.006 to 7.121 (gcm−3) and 146.579 to 178.823 (g) as Na2O was replaced by PbO. The direct and indirect bandgap energies decreased from 3.512 to 3.357 and 2.791 to 2.525 eV as the lead concentration increased from Pb40Na20–Pb60Na0. We employed the Geant4 simulation code for narrow-beam geometry with a mono-energetic photon beam imposed on a glass specimen. The mass attenuation coefficient (µ/ρ) for the fabricated glass was determined using the Geant4 simulation code. The difference between the theoretical values (XCOM) and simulated values (Geant4) was less than 7%, confirming the accuracy of the present results. The µ/ρ values increased quickly with the increasing PbO content at low photon energies, while increasing the energy reduced the increase of the µ/ρ values. The linear attenuation coefficient (LAC) was also evaluated and the results showed that increasing the density increased the attenuation behavior. The Pb60Na0 sample with the highest density (7.121 g/cm3) had the largest LAC values at all energies (in the range of 0.29–1.69 cm−1). The effective atomic number values of the fabricated samples were in the range of 33–70. Pb60Na0 glass with the lowest half-value layer is a promising candidate for radiation-shielding applications among Pb40Na20–Pb60Na0 glass.

Structural, elelectrical and energy storage properties of BaO–Na2O–Nb2O5–WO3–P2O5 glass–ceramics system

Ferroelectric glass-ceramics are promising composite materials with dual properties, of high dielectric permittivity and high dielectric breakdown strength. In this context, new phosphate glass-ceramics 2BaO-0.5Na2O–2.5[(1 − x)Nb2O5–xWO3]-1P2O5 (x = 0, 0.1, 0.2, 0.3 and 0.4) designated as B0, B1, B2, B3, B4 respectively, were prepared by the controlled crystallization technology and then crystallized at high temperature of 760 °C for 10 hours. Subsequently, the obtained glass-ceramics were studied by Differential Scanning Calorimetry (DSC), x-ray powder diffraction (XRD), Raman, impedance spectroscopy, and the P-E hysteresis loops. All of these techniques allowed the identification of Ba2Na4W2Nb8O30 phase with tungsten bronze structure embedded in the glassy matrix. The density of glass-ceramics was found to increase with increasing tungsten content to reach a maximum at x = 0.3 and then decreases. Dielectric and conductivity parameters were found to be governed by the presence of oxygen vacancies. Room temperature energy storage property which depends on the composition X, was performed using P-E hysteresis loops of the glass-ceramics. The optimum discharge density was obtained for B3 with an energy efficiency of 73.77%.