B2O3 SiO2 Research Articles

Effect of BN addition on mechanical and electrical properties of oxidative sintered porous Si3N4-BN composites

In order to explore the effects of BN addition on the mechanical and electrical properties of oxidative sintered Si3N4-BN composites, Si3N4-BN composites with BN powder dosage of 0-40 wt% are prepared by molding technology, and the effects of different BN contents on the phase, morphology, bulk density, porosity, flexural strength at room temperature, dielectric constant and dielectr loss of the composite system are studied. With the increase of BN content, at different temperatures, the oxidation product B2O3 of BN and the oxidation product SiO2 of Si3N4 firstly react on the surface to form B2O3–SiO2 glass phase, which densify the surface and affects the oxidation degree of internal grains. At the same time, a small amount of B2O3 escaping from the surface, so that the open pores of the composites decrease firstly and then increase slightly, and the dielectric constant increases firstly and then decreases. The results show that when the amount of BN micronized powder is 10 wt%, the oxidation sintered Si3N4-BN composite material at 1500 °C have pores that retain the sheet structure of boron nitride, and the amorphous material flows to fill the pores, so it have high volume density (1.85 g/cm3), low porosity (apparent porosity 6.37%), and high mechanical properties (flexural strength 127.86Mpa), higher dielectric constant (3.94) and lower dielectr loss (4.0 × 10−4).

Glass Microspheres Thermo-Deformation Sintering Processes in the Technologies of Obtaining Materials for Underwater Technical Equipment

Abstract In this work, the important scientific and technical problem of creating multifunctional composite materials for shipbuilding and ocean engineering was solved. The work aimed to study the thermal deformation processes of sintering glass microspheres to obtain lightweight glass composites with a cellular structure that provides positive buoyancy and sound insulation properties. For this purpose, glass microspheres of Na2O‒SiO2 and Na2O‒B2O3‒SiO2 composition with a dispersion of 10 to 60 μm were used as raw materials. They were sintered to form a closed, porous structure. The theoretical substantiation of technological parameters is based on the concepts of solid state and glassy state chemistry and physicochemical concepts of glass softening processes. The process of hot-pressing glass microspheres without plasticisers and additives was investigated. The author’s own laboratory equipment was used for the experiments. The sintering intensity was determined from the results of shrinkage processes; the kinetic shrinkage curves were constructed in semilogarithmic coordinates. The glass composite samples were examined by optical and electron microscopy. As a criterion, the storage of spherical microspheres under the influence of simultaneous heating to 700 °C with the application of pressure in the range of 0,5 to 1,5 MPa was chosen. It was established that the formation of a predominantly closed-porous structure of glass composites with a density of 350...600 kg/m3 occurs by the mechanisms of viscous glass phase flow through liquefaction processes in the walls of microspheres. At the same time, shrinkage processes in the linear direction reach up to 50%. The acoustic properties were investigated by measuring the differences in sound pressure levels in octave frequency bands using a Kundt pipe. The water absorption of the glass composite samples was determined at hydrostatic pressures up to 20 MPa. The research results were compared with the characteristics of analogue composites, such as syntactic foams and foam glass. The developed materials can be used in the design and manufacture of technical equipment for research and maintenance of underwater infrastructure. The prospects for further research are related to the feasibility study and marketing research on implementing the developed glass composites.

Enhanced thermal conductivity and mechanical performance of CaO–B2O3–SiO2 glass ceramic with AlN addition for LTCC applications

As electronic devices with high integration and reliability are developed, the need for electronic packaging materials with good thermal conductivity, dielectric properties, and mechanical properties has increased. In this study, a CaO–B2O3–SiO2 (CBS) glass ceramic with added aluminium nitride (AlN) was prepared via tape casting and solid phase sintering. The sintering behavior, phase compositions, microstructure, thermal conductivity, mechanical properties, and dielectric properties of the material were investigated. The addition of AlN greatly enhanced the thermal conductivity and improved the mechanical properties of the composite. The CBS/AlN composite with 40 wt% AlN sintered at 860 °C for 20 min exhibited excellent performance with a thermal conductivity of 6.23 W/(m⋅K), a coefficient of thermal expansion (CTE) of 6.11 ppm/°C, a flexural strength of 212.6 MPa, a dielectric permittivity of 7.2–7.36 with a relatively low dissipation factor of 0.0003–0.002 (1 kHz–10 MHz), and a weak temperature dependence of the dielectric permittivity. Moreover, the excellent chemical compatibility with silver made such CBS/AlN composites a promising material for electronic substrate applications.

Preparation, Absorption Spectra, and Luminescence Properties of Er2O3- and Yb2O3-Doped Oxyfluoride Glasses in the SrF2–SiO2–B2O3–Bi2O3–ZnO–Y2O3 System

Preparation, Absorption Spectra, and Luminescence Properties of Er2O3- and Yb2O3-Doped Oxyfluoride Glasses in the SrF2–SiO2–B2O3–Bi2O3–ZnO–Y2O3 System

Enhancing thermal and dielectric properties of MgO–Al2O3–SiO2–B2O3 glass-ceramics through CuO doping

In this work, (20-x)MgO–20Al2O3–56SiO2–4B2O3-xCuO (x = 0, 0.25, 0.5, 0.75, 1, 1.25 mol%) glass-ceramics were synthesized by solid-state reaction method. The crystallization, microstructure, thermal and dielectric properties of (20-x)MgO–20Al2O3–56SiO2–4B2O3-xCuO glass-ceramics was discussed in detail. It was demonstrated that the CuO lowers the crystallization temperature of α-cordierite and promotes the crystallization process of MgO–Al2O3–SiO–B2O3 glass-ceramics. Thus, the crystallization showed a substantial influence on the dielectric properties, as evidenced by an elevation in dielectric constant and a decrease in dielectric loss. Specifically, with the addition of 0.5 mol% CuO, the MgO–Al2O3–SiO–B2O3 glass-ceramics sintered at 1050 °C shows excellent properties of: εr = 5.04, tanδ = 2.2 × 10-4, κ = 3.4 W/mK and α = 1.75 × 10-6/°C. These works provide valuable insights into the design and development of (20-x)MgO–20Al2O3–56SiO2–4B2O3-xCuO glass-ceramics with tailored properties for structure/function integration in the electronics industry.

Metal-oxide doping enhances electromagnetic wave absorption performance of BaFe12O19 glass-ceramics

Elimination or reduction of electromagnetic wave pollution is receiving increasing attention; development of high-performance wave-absorbing materials has become key to solving this problem. In this study, BaFe12O19 crystals were precipitated in a BaO–Fe2O3–B2O3–SiO2 glass system using the melt-quench-second heat treatment method. The microstructure and magnetic properties of the BaFe12O19 glass ceramics and their electromagnetic wave loss characteristics were analyzed. The composition of the crystals in the glass can be modified by introducing other metal oxides, such as ZrO2 (BFO-Z), TiO2 (BFO-T), and Al2O3 (BFO-A), to enrich the heterogeneous interfaces and increase the dielectric loss of the material. The maximum effective absorption bandwidth of BaFe12O19 glass-ceramics with addition of ZrO2 (BFO-Z) was increased to 3.20 GHz; the minimum reflection loss was reduced to −45.60 dB. This simple method represents a new direction for fabricating high-performance wave-absorbing materials.

Interpretation of the resistance of Li7La3Zr2O12 – Li2O–B2O3–SiO2 composite electrolytes for all–solid–state batteries using the distribution of relaxation times technique

Solid electrolytes based on Li7La3Zr2O12 are promising membranes for all–solid–state batteries. However, the main parameters of all transport stages in composite and doped Li7La3Zr2O12 could not be determined by conventional impedance fitting. A tremendous assistance in the analysis of impedance spectra over the past few years has become the method of distribution of relaxation times (DRT). In the present study, a composite electrolyte Li7La3Zr2O12 – Li2O–B2O3–SiO2 was investigated by impedance spectroscopy. A detailed analysis of the impedance spectra by DRT showed that the additional peak appears on the DRT function with the introduction of glass; this interfacial resistance is responsible for the transfer of lithium ions across the Li7La3Zr2O12/glass interface. The resistance, capacitance and relaxation frequency of all the transport stages in the composite electrolytes were determined based on the analysis of the DRT functions. It was found that the Li7La3Zr2O12/glass resistance decreases with increasing fraction of glassy additive. It was established that the DRT technique can be successfully used to deeper understanding of the transport stages of lithium ions in composite and doped solid electrolytes for all–solid–state batteries.

Cation field‐strength effects on ion irradiation‐induced mechanical property changes of borosilicate glass structures

AbstractWe examine the impact of the glass network‐modifier cation field strength (CFS) on ion irradiation‐induced mechanical property changes in borosilicate (BS) glasses for the ternary M2O–B2O3–SiO2 systems with M = {Na, K, Rb} and the quaternary [0.5M(2)O–0.5Na2O]–B2O3–SiO2 systems with M = {Li, Na, K, Rb Mg, Ca, Sr, Ba}. 11B nuclear magnetic resonance (NMR) experiments on the as‐prepared BS glasses yielded the fractional population of four‐coordinated B species (B[4]) out of all {B[3], B[4]} groups in the glass network, along with the fraction of B[4]–O–Si linkages out of all B[4]–O–Si/B bonds. Both parameters correlated linearly with the (average) CFS of the M+ and/or {M(2)+, Na+} cations. Both the nanoindentation‐derived hardness and Young's modulus values of the glasses reduced upon their irradiation by Si2+ ions, with the property deterioration decreasing linearly with increasing Mz+ CFS, that is, for higher Mz+⋅⋅⋅O interaction strength. The irradiation damage of the glass network also increased linearly with the fraction of B[4]–O–Si linkages, which are the second weakest in the structure after the Mz+⋅⋅⋅O bonds. Our results underscore the advantages of employing BS glasses with high‐CFS cations for enhancing the radiation resistance for nuclear waste storage.

Low-temperature sintering and phase component modulation of 0.95MgTiO3–0.05CaTiO3 microwave dielectric ceramics

This study prepared glass doped 0.95MgTiO3–0.05CaTiO3 (95MCT) ceramics with excellent microwave dielectric properties via phase constituent regulation. Based on XRD and semi-quantitative analysis, it is found that the types of glass, addition amounts of glass, and sintering method can introduce different phase compositions. With the aid of the low softening point for glass materials and the liquid phase sintering mechanism, the 95MCT ceramics can be densified at a relatively low temperature. Meanwhile, based on the mixture rule, adjusting the proportion of each phase structure by altering the sintering method, the optimum temperature (1200 °C) for 95MCT ceramics is reduced by about 200 °C without deteriorating performance. Typically, the 95MCT ceramic doped with 1 wt % ZnO–B2O3–SiO2 glass demonstrates excellent microwave dielectric properties: εr = 18.3, Q × f = 50824 GHz (@7.9 GHz).

Thermal, mechanical characteristics as well as gamma-ray shielding capabilities of sodium-barium borosilicate glasses with Y3+ ions

By using a melt-quench procedure, the bulk, transparent, and homogenous B2O3–SiO2– BaO– Na2O glasses with varied mol% of Y2O3 added were masterfully synthesized. The unstructured behavior of the samples was shown by X-ray diffraction examination. According to the data, the sample (G 5) has the maximum density (3.894 g/cm3) when compared to other samples. The G 5 sample appears to have the highest compactness at the same time that the G 1 sample has the lowest compactness. Shear waves (VT) increased from 2820 to 2960 m/s & longitudinal velocity (VL) increased from 4930 to 5225 m/s. DTA study found that the structural alterations can be connected to the increase in (VL)&(VT). Furthermore, Phy-X code was used to determine the radiation shielding characteristics. Our results demonstrated that, in terms of LAC and MAC, the produced samples' capacity against gamma is arranged as follows: (G5)MAC,LAC> (G4)MAC,LAC> (G3)MAC,LAC> (G2)MAC,LAC> (G1)MAC,LAC. The glass G 5 outperformed most of the other glasses, which suggests that it has a possibility to be used in shielding applications.

Unveiling the structural, optical, and electromagnetic attenuation characteristics of B2O3–SiO2–CaO–Bi2O3 glasses with varied WO3 content

This study provides insight into B2O3–SiO2–CaO–Bi2O3 glasses where novel results for the effects of WO3 content on its structural and optical properties have been demonstrated. Thus, provides useful data for developing new glasses for optical and electromagnetic shielding applications. The effect of WO3 content on the structural and optical properties of B2O3–SiO2–CaO–Bi2O3 glasses was investigated along with radiation shielding features which have been calculated by XCOM program. BSCB/W-00, BSCB/W-2.5, BSCB/W-5.0, BSCB/W-7.5, BSCB/W-10, BSCB/W-15, and BSCB/W-20 refer to seven samples of bismuth borosilicate glass system doped with 0.0, 2.5, 5, 7.5, 10, 15, and 20% of WO3, respectively, synthesized using the melt quenching technique. The density of the glasses decreased with increasing WO3 content due to the replacement of Bi2O3 with lower-density WO3. It was found that the absorption coefficient decreased with increasing WO3 content up to 10 wt%, but showed an opposite trend for samples with higher WO3 content. The optical band gap and the transition type were affected as the WO3 content increased. The electromagnetic wave decay or skin depth was also calculated. Overall, the shielding effectiveness of investigated samples BSCB/W-00, BSCB/W-2.5, BSCB/W-5.0, BSCB/W-7.5, BSCB/W-10, BSCB/W-15, and BSCB/W-20 has reduced with the enlargement of the WO3 concentration. BSCB/W-00, out of all the samples tested, has the highest shielding efficiency.

Ultra-high-frequency radio-transparent ceramics of cordierite composition doped with MgO–Al2O3–B2O3–SiO2 glass: Synthesis, microstructure, thermal and physical properties

The paper presents the results of a study of radio-transparent cordierite ceramics, in which a part of the components was introduced using the eutectic glass of the MgO–Al2O3–SiO2 pseudoternary system. The formation of α-cordierite occurs during the sintering of ceramics due to the intensive interaction of components of the eutectic glass with crystalline fillers, as well as due to the crystallization of glass. At the same time, densely sintered material was obtained at relatively low temperatures (1300–1350°С). The crystalline phase of α-cordierite fully forms the structural matrix of the ceramic material. Crystals of the cordierite phase are formed in the form of regular-shaped flat prisms, mostly 1–3 μm in size. The pores between cordierite crystals are completely filled with glassy phase, which ensures their strong connection, uniform and dense microstructure of the material, as well as high strength, dielectric and thermal characteristics.

A comparison study on the dissolution mechanism of Al2O3 inclusion on fluorine-bearing and fluorine-free molten mold fluxes

The dissolution mechanism of Al2O3 inclusions in molten slags was explored by in-situ single hot thermocouple technique combined with X-ray photoelectron spectroscopy. Result shows that it takes 2940 s to completely dissolve Al2O3 inclusions in the molten F-bearing mold flux, which is mainly controlled by boundary layer diffusion. Because the connected [AlO6] octahedra in the Al2O3 inclusion is gradually destroyed by the O2− ions in the melt. By comparison, the CaO–SiO2–B2O3 based F-free mold flux only takes 840 s to completely dissolve Al2O3 inclusions. Because the [AlO6] octahedra is destroyed and further transformed to [AlO4] tetrahedra and produce O2− ions, which greatly facilitates the dissociation of the Al2O3 particle. However, the formed [AlO4] tetrahedra will promote the precipitation of the dense 2CaO·SiO2·Al2O3 crystals, which tightly encases the Al2O3 particle and causes significant drop in the dissolution rate. Thus, the dissolution rate is controlled by chemical reaction and then by boundary layer diffusion.

Anti-acid corrosion mechanism of yttrium oxide doped barium borosilicate glass

Designing glass with excellent acid resistance is a prerequisite for developing high-performance terminal electrode pastes. Herein, we fabricated Y2O3 doped BaO–B2O3–SiO2 glass with excellent anti-sulfuric acid corrosion properties. The anti-corrosion mechanism of glass in acid environment was investigated by spectra and microstructure analysis. The passivating gel layer with a porous structure was formed on the glass surface during the corrosion process. The average pore diameter of the porous gel could be reduced by increasing the content of Y2O3. The smaller pore size of the porous gel would considerably increase the collision frequency between solvent molecules and the pore wall, which could effectively inhibit the ion migration in the gel layer, reduce the corrosion rate, and improve the acid resistance of the glass. This study contributes to the understanding of the corrosion mechanism of the glass and provides theoretical guidance for rationally designing anti-acid corrosion glass for terminal electrode pastes.

Degradation-controlling mechanisms in natural organic acid solutions of CaO–Al2O3–SiO2–B2O3 glass-ceramics by partially substituting Ca2+ with Ba2+ and Sr2+

The degradation of environmentally friendly CaO–Al2O3–SiO2–B2O3 (CASB) glass-ceramics, which consist of anorthite and glass phase, was investigated in three natural organic acid solutions. The results indicated that citric acid had the most significant effect on the degradation of CASB glass-ceramics. While the chemical stability of anorthite is relatively poor, the glass phase also contributed significantly to the effective degradation of CASB glass-ceramics. Subsequently, Ba2+ or Sr2+ was used for full or partial substitution of Ca2+ in CASB glass-ceramics, and the degradation-controlling mechanism of the substituted CASB glass-ceramics was further researched. The full substitution of Ca2+ in CASB glass-ceramics by the two cations resulted in the occurrence of borate [BO4] units in the glass phases, and the interlinkage of [BO4] with broken silicate [SiO4] network structures caused a complementary network effect. Consequently, the degradation of CASB glass-ceramics by organic acids was reduced due to the improvements in the chemical stability of the modified glass-ceramics. Additionally, degradation control can also be achieved based on a mixed-alkali effect, originating from the partial substitution of Ca2+ in CASB glass-ceramics by Ba2+ or Sr2+. The degradable glass-ceramics have the potential to be applied in low-temperature co-fired ceramic technology because of their good physical properties, which include a dielectric constant of 3–5, a dielectric loss as low as 10−3, a coefficient of thermal expansion of 3–9 × 10−6/°C, and an average bending strength of about 47 MPa. Noticeably, the development of the degradable glass-ceramics is helpful to the low-cost and pollution-free recycling of valuable metal electrodes, which is significant for the sustainable development of electronic packaging technologies.

Phase transformation and mechanical properties of new bioactive glass-ceramics derived from CaO–P2O5–Na2O–B2O3–SiO2 glass system

This work investigates the role of sintering temperature on bioactive glass-ceramics derived from the new composition CaO–P2O5–Na2O–B2O3–SiO2 glass system. The sintering behaviour of the samples’ physical, structural, and mechanical properties is highlighted in this study. The experimental results indicated that the sintering process improved the crystallization and hardness of the final product. Results from XRD and FTIR showed the existence of carbonate apatite, pseudo-wollastonite, and wollastonite phases. From the results, the bioglass-ceramics sintered at 700 °C obtained the highest densification and optimum mechanical results. It had the value of 5.34 ± 0.21 GPa regarding microhardness and 2.99 ± 0.24 MPa m1/2 concerning fracture toughness, which falls in the range of the human enamel. Also, the sintered samples maintained their bioactivity and biodegradability after being tested in the PBS medium. The bioactivity does not affect but slows down the apatite formation rate. Overall results promoted the novel bioglass-ceramics as a candidate material for dental application.

Temperature-stable and medium-high K of Ti/W co-doped M-phase LNT microwave ceramics for LTCC dielectric devices

The increasing demand for miniaturized electronic devices requires the development of advanced medium-high K materials. In this work, novel (Ti1/2W1/2)5+-substituted LiNb0.6-x(Ti1/2W1/2)xTi0.5O3 (LNT-xTW, 0 ≤ x ≤ 0.12) ceramics were successfully prepared by the solid-state method. The increase in TW content led to the formation of LNT-0.08 TW ceramic with medium-high K and high Q × f after sintering at 1050 °C. This ceramic also recorded improved characteristics with εr∼53.84, Q × f∼7482 GHz and τf∼43.43 ppm/°C related to ionic polarizability, large grains, high densification, and [Ti2O3]2+/N layers. In addition, Li2O–B2O3–SiO2–CaO–Al2O3 (LBSCA) used as an effective sintering aid, improved densification and promoted sintering by not only decreasing the temperature to 900 °C, but also enhancing the microwave dielectric properties with εr∼49.46, Q × f∼8149 GHz, and τf∼12.04 ppm/°C. The Q × f value was estimated to 1.15 ∼ 2-fold higher than other LNT-based ceramics within stable τf. More encouragingly, the LNT-0.08 TW ceramic also showed good chemical match with Ag, suggesting usefulness for miniaturized LTCC devices.

Comprehensive In Vivo and In Vitro Studies for Evaluating the Bone-Bonding Ability of Na2O–CaO–SiO2–B2O3–Ag2O Glasses for Fracture Healing Applications

In the present investigation, Na2O–CaO–SiO2–B2O3–Ag2O glasses were prepared using the traditional melt-quenching process, with Ag2O content progressively raised from 0 to 4 wt.%, at the expense of B2O3, in the chemical composition of these glasses. The created glasses’ physical, mechanical and electrical characteristics were measured. The bone bonding capacity of the as-prepared specimens was evaluated not only by in vitro studies with treatment in simulated body fluid but also by in vivo studies using the albino rat model at different time intervals up to 28 days. The obtained findings revealed that increasing the Ag2O content gradually improved the fracture toughness of the samples by approximately 3.94, 11.84, 27.63, 50%, but fortunately with slight decreases in the microhardness, i.e. 1.02, 2.73, 8.90 and 16.43% and other mechanical properties. All samples had electrical conductivities of 2.36, 2.65, 2.84, 3.59, and 4.23 × 10‒5 S/m when the frequency was 1 MHz, compared to 1.36, 1.58, 1.72, 2.10, and 2.42 × 10‒4 S/m for the same samples at 20 MHz. Furthermore, the addition of Ag2O had a favorable function in improving the bioactivity of the glass samples, as evidenced by in vitro and in vivo data, and no cytotoxicity was seen. Based on these attractive findings, it is possible that the produced glass samples would be suitable for orthopedic applications at load-bearing-sites.Graphical

Regulation of luminescence properties of Gd2O3–B2O3–SiO2–Na2O–Al2O3 glasses by the content of Eu3+

Regulation of luminescence properties of Gd2O3–B2O3–SiO2–Na2O–Al2O3 glasses by the content of Eu3+

Effect of Oxides of Various Metals on the Physicochemical Properties of Glass in the PbO–CdO–SiO2–B2O3–Al2O3 System

Effect of Oxides of Various Metals on the Physicochemical Properties of Glass in the PbO–CdO–SiO2–B2O3–Al2O3 System