Preparation of transparent Bi2O3-ZnO-B2O3 glass by conventional sintering at low temperatures

Glass components fabricated by the sintering route have wide-ranging applications. However, one issue is that the crystallization tendency of glass powders often leads to residual pore-glass interfaces and crystal-glass interfaces, thereby causing strong light scattering and rendering the sintered glass opaque. This issue is particularly pronounced in glasses with a low glass transition temperature (T_g) due to their weak bonding and thus high crystallization tendency. In the present study, a Bi₂O₃-ZnO-B₂O₃ glass with a low T_g of 364°C was fabricated using the conventional sintering method to explore whether transparent glass materials can be obtained. The temperature range of crystallization of the glass powders was analyzed using differential scanning calorimetry. X-ray diffraction was employed to analyze the crystalline phases formed in the sintered glasses. The microstructure of the sintered glasses was examined using scanning electron microscopy. The optical transmittance of the sintered glasses was measured using ultraviolet-visible spectroscopy. The results show that transparent sintered glasses with the highest transmittance of 54% at the wavelength of 650 nm can be obtained by using a coarser initial particle size, lower forming pressure, and an appropriate sintering temperature/time (430°C/30 min). It is suggested that this combination of processing parameters can suppress glass crystallization while maintaining a low glass viscosity during sintering.     

Lightweight aggregate based on waste glass and its alkali-silica reactivity

The possible use of waste glass for the production of lightweight aggregate has been studied. The aggregate, in the form of highly porous granules, was produced by mixing together finely ground waste glass and an expansive agent and firing this mixture at a selected temperature. The expansive agent was chosen on the basis of the results of DTA/TGA experiments, which were carried out on some selected agents and confirmed by using a hot-stage microscope, where the temperature interval of the expansion was also determined. Pilot production of about 0.5 m³ of the aggregate was performed in a rotary kiln, and the water absorption and bulk density of the aggregate so obtained were determined. Special emphasis was placed on the determination of the alkali-silica reactivity of the aggregate, and the results of initial tests for alkali-aggregate reaction were encouraging, given the high potential reactivity of the material. However, before such aggregate can be considered safe for general use in concrete, longer-term concrete prism tests need to be carried out, which would cover the range of mixes in which the aggregate is likely to be used.     

Bi_2O_3–ZnO–B_2O_3三元系统玻璃结构与性能

采用X射线吸收精细结构和红外吸收光谱分别对铋锌硼玻璃中铋离子邻近结构和硼氧网络结构进行研究,分析其结构变化对玻璃转变温度Tg和热膨胀系数α的影响。结果表明:1)铋离子以三配位([BiO3])和六配位([BiO6])两种配位状态存在;随Bi2O3含量增加,三配位铋离子的配位数上升,六配位铋离子配位数下降,同时铋离子总配位数上升。2)随Bi2O3含量增加,硼氧网络中硼氧四面体含量下降,硼氧三角体含量上升,硼氧四面体网络解聚形成硼氧三角体网络。3)上述结构因素是造成玻璃转变温度Tg下降和热膨胀系数α上升的主要原因。     

机械振动辅助Bi2O3-ZnO-B2O3三元玻璃料浆均匀化机理

通过数值模拟研究了机械振动下Bi₂O₃-ZnO-B₂O₃三元玻璃料浆的混合过程,并分析了混合均匀化机理。首先,利用旋转黏度计分别测量了Bi₂O₃、ZnO及B₂O₃三种玻璃料浆的黏度,并用光学显微镜分别观察三种玻璃料浆的粒度,通过Stokes-Einstein方程得到流体料浆的扩散系数。在此基础上建立了机械振动下Bi₂O₃-ZnO-B₂O₃三元玻璃料浆混合过程的Fluent模型,定义了描述三元料浆混合均匀程度的混合偏差。通过模拟研究发现：①增加容器振幅及频率均能加快三元料浆的混合;②机械振动的振幅及频率不宜过高,否则会导致料浆溢出容器;③混合偏差随时间增加而降低,可以通过幂函数描述,从而可以预测不同振幅和频率下Bi₂O₃-ZnO-B₂O₃三元玻璃料浆的混合均化时间。指出选择合适的振幅及频率,有助于提高混合效率,并避免料浆溢出容器。     

Experimental study on foam glass prepared by hydrothermal hot pressing-calcination technique using waste glass and fly ash

Foam glass is a lightweight and high-strength building and decoration material with superior performance in heat insulation, sound absorption, moisture resistance and fire protection. The use of waste glass powder and fly ash to prepare foam glass is one of the most important ways to utilize solid waste as a resource. In this study, waste glass powder and fly ash were used as raw materials to prepare foam glass by a hydrothermal hot pressing–calcination method. The effects of fly ash content (0 wt%, 10 wt%, 20 wt%, 30 wt%), heating rate (1 °C/min, 3 °C/min, 5 °C/min, 8 °C/min, 10 °C/min) and calcination temperature (600 °C, 700 °C, 750 °C, 800 °C, 850 °C, 900 °C) on the microscopic morphology, density, compressive strength, porosity and other properties of the foam glass samples were studied. Their microstructure and morphology were analyzed by thermogravimetric analysis–mass spectrometry, X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. At a fly ash content of 10 wt%, the heating rate was 5 °C/min, the calcination temperature was 800 °C, the foam glass density was 0.3 g/cm³, the compressive strength was 1.65 MPa, the total porosity was 75.5%, and the effective thermal conductivity was 0.206 W/m·K. The effective thermal conductivity models of the composite materials were used to verify the experimental data. The relationship between the thermal conductivity of foam glass materials and the related influencing factors was investigated.     

Bi_2O_3-B_2O_3-BaO玻璃的结构与热学性能研究

通过调整ω(Bi_2O_3)/ω(BaO)比例关系,研究了Bi_2O_3-B_2O_3-BaO低熔点玻璃体系结构和性能,通过DTA测定了玻璃软化温度和转变温度,热膨胀测试仪测试玻璃膨胀系数,红外光谱仪和X射线衍射仪分别研究玻璃结构和玻璃化程度。结果表明:玻璃的软化温度和转变温度都随着BaO质量分数的增加而增加,两者均处于较低的温度变化区间;玻璃的热膨胀系数随着BaO质量分数的增加而升高,XRD表明,玻璃的玻璃化程度良好,没有析晶。     

Pulse energy-storage performance and temperature stability of Bi2O3-added BaTiO3 based ceramics

The temperature stability and temperature stability range of barium titanate-based pulse energy-storage ceramics were modified by Bi₂O₃ tailoring in (Ba_0.98-xLi_0.02Bi_x) (Mg_0·04Ti_0.96)O₃ (x = 0, 0.025, 0.05, 0.075, 0.1) and (Ba_1.03-1.5xLi_0.02Bi_x) (Mg_0·04Ti_0.96)O₃ (x = 0.125, 0.15, 0.2, 0.25) ceramics. Excellent pulse energy-storage performances of ceramic films are achieved via the new dual priority strategy of establishing cationic vacancies and forming a liquid phase. The dielectric constant plateau appears due to the cubic phase and space charges. Outstanding temperature stability, frequency stability and antifatigue performance are obtained in the ceramics, and their variations are all less than 15%. The comprehensive energy-storage properties with dual priority parameters of energy-storage density and efficiency of 3.13 J/cm³ and 91.71%, accompanied by an excellent pulse discharge energy density of 2.48 J/cm³, current density of 1313.23 A/cm² and power density of 195.26 MW/cm³ are gained at x = 0.1. The perfect pulse energy-storage performances as well as ultrahigh stability are correlated with synergistic effects of multiphase coexistence, cubic phase, liquid-phase sintering, grain size, ceramic resistance, space charges and polar nanoregions. The comprehensive parameters indicate that the (Ba_0·88Li_0·02Bi_0.1) (Mg_0·04Ti_0.96)O₃ ceramics have potential application in high precision fields.     

Effect of Bi2O3 on mechanical features and radiation shielding properties of boro-tellurite glass system

This paper focuses on the effect of Bi₂O₃ content (up to 80 mol%) on mechanical features and radiation shielding characteristics of boro-tellurite glasses within TeO₂–B₂O₃–Bi₂O₃ system. The basic mechanical parameters such as oxygen molar volume, packing density, hardness, and elastic moduli were studied based on Makishima–Mackenzie's theory. The shielding studies of the TeO₂–B₂O₃–Bi₂O₃ glasses included gamma, electron and neutron radiations. The newly developed Phy-X/PSD program and Geant4 simulation were used to calculate the shielding parameters such as mass attenuation coefficient (μ/ρ), tenth value layer (TVL), mean free path (MFP), stopping power (ψ_e)), removal cross section (RCS), CSDA range, effective atomic number (Z_eff), and half value layer (HVL). The concentration of Bi₂O₃ content had a significant effect on the gamma shielding competence of the investigated glasses. Form the results of gamma shielding studies, the highest μ/ρ (99.845 cm²/g) occurred at 0.015 MeV for TBB80 and the lowest μ/ρ (0.039 m²/g) occurred at 4 MeV for TBB40. The maximum values of Z_eff for gamma interaction occurred at 0.02 MeV and they were 77.26, 78.81, 79.94, 80.80, and 81.48 for TBB40, TBB50, TBB50, TBB60, TBB70, and TBB80, respectively. The gamma shielding features of the investigated glasses were compared with those of various ordinary concretes, and Pb-free, Pb-based, and commercial glasses. The Bi₂O₃ content had also a considerable influence on the electron shielding competence of the tested glasses. The maximum values of Z_eff for electron interaction occurred at 14 MeV and they were 44.58, 47.72, 50.41, 52.75, and 53.73 for TBB40, TBB50, TBB50, TBB60, TBB70, and TBB80, respectively. The results revealed that the bismuth boro-tellurite glasses could be useful for the shielding against gamma, electron, and neutron radiations, wherein the Bi₂O₃ content can be balanced according to the type and energy of radiation.     

Tailoring the efficient laser-absorption-melting behavior of Bi2O3-B2O3-ZnO-Nd2O3 glass for the OLED encapsulation

The efficient 810 nm laser energy conversion of glass frit had been proven to be the key to the long-term hermetic encapsulation of Organic Light Emitting Display (OLED). A direct laser energy conversion laser-assisted Bi₂O₃-B₂O₃-ZnO-Nd₂O₃ sealing glass material without extra laser absorbent such as carbon black, was designed and systematically investigated. The addition of Nd₂O₃, as glass modifiers with higher cationic field strength, could be conducive to enhancing the polymerization of glass network structure, manifesting that the glass-transition temperature Tg, onset-crystallization temperature Tc and thermal stability ΔT (ΔT = Tc-Tg) increased, while thermal expansion coefficient CTE dropped to 9.72×10⁻⁶/°C and advantageously matched with the glass substrate (8±1×10⁻⁶/°C). More importantly, the absorption rate of BBZ-Nd glass was more than 50 % between 800∼810 nm owing to the 4f-4f electron transition of Nd³⁺ ions, and yet the reflectivity and transmittance of the wavelength at 800–810 nm were lower. As optimal compositions, the addition of 3.0 wt% Nd₂O₃ in Bi₂O₃-B₂O₃-ZnO-Nd₂O₃ glass frit with higher absorption coefficients (80 %) led to instantaneous bonding encapsulation between glass substrates without interfacial cracks or pores with the 808 nm wavelength of the laser at 20 W and 2.4 mm/s.     

Influence of Bi2O3/WO3 substitution on the optical,mechanical, chemical durability and gamma ray shielding properties of lithium-borate glasses

Six different lithium bismuth boro-tungstate glasses with chemical composition 20Li₂O-(20-x)Bi₂O₃-xWO₃-60B₂O₃ (x = 0, 1, 2, 3, 4 and 5 mol%) were produced by the quenching method. Then, the glasses were investigated by means of their optical, mechanical, chemical durability and gamma ray shielding properties. Measured values of density and ultrasonic velocities were used to determine the elastic properties of the glasses. The optical band gap determined using the absorbance spectrum fitting (ASF) model was found to decrease under Bi₂O₃/WO₃ substitution. The presence of BO₃, BO₄, BiO₆, and WO₄ structural groups in the glasses was confirmed by Fourier transform infrared spectroscopy (FTIR). The dissolution rate in the glass 20Li₂O–15Bi₂O₃–5WO₃–60B₂O₃ (LBWB5) was found to be 10 times lower than 20Li₂O-20Bi₂O₃– 60B₂O₃. Mass attenuation coefficients (MAC) values of the produced glasses were determined using the MCNPX Monte Carlo code and Phy-X/PSD program. The photon attenuation parameters such as half value layer (HVL), mean free path (MFP), effective atomic number (Z_eff), exposure buildup factor (EBF) and energy absorption buildup factor (EABF) were also studied. The obtained results showed that Bi₂O₃/WO₃ substitution has a direct impact on the photon attenuation abilities of produced glasses. More specifically, HVL values increased from 0.252 × 10^?2 cm for LBWB0 glass to 0.275 × 10^?2 cm for LBWB5 glass. However, different trends were observed for the photon buildup factors for the produced glasses. It can be concluded that the produced glasses have promising structural, optical, and photon attenuation properties to be used for gamma shielding applications.     

Preparation and properties of foam ceramic from nickel slag and waste glass powder

The utilisation of nickel slag and waste glass powder as raw materials for preparing foamed ceramic was studied. The influences of the mixture design and foaming-agent dosage on the properties and microstructures of foamed ceramic were investigated in terms of the density, flexural strength, phase composition and micromorphology. Results showed that incorporating nickel slag improved the flexural strength and uniformity of the pore structure. However, owing to the high density of nickel slag, its excessive usage may impact the development of foamed ceramic density and porosity as a side effect. The Na₂CO₃ dosage was another crucial factor determining foamed ceramic properties. A nickel slag content of was 20% and a Na₂CO₃ content of 7% decreased the foamed ceramic density to 0.498 g/cm³, with a corresponding flexural strength of 2.66 MPa and a higher porosity of 80.06%.     

Comparative investigation of physical,X-ray and neutron radiation shielding properties for B2O3-MnO2-CdO borate glasses

B₂O₃-MnO₂-CdO ternary oxide glasses with amorphous properties were synthesised using the melt-quenching method. Structural and physical property analyses showed that the amount of non-bridging oxygen and the system stiffness increases, and the oxide network filling is more tightly packed as cadmium oxide (CdO) gradually replaces manganese Oxide (MnO₂) in the glass. The radiation-shielding performance of the B₂O₃-MnO₂-CdO glasses was evaluated using the shielding parameters calculated by the MCNPX simulation and the Phy-X program. Glasses with 40% and 50% CdO loading exhibited an average specific lead equivalent (PbE) of 0.241 and 0.294 mmPb/mm in the medical X-ray diagnostic area at 0.03–0.08 MeV; thus, they could fully meet the specific PbE requirements for application as "protection devices against diagnostic medical X-radiation". Furthermore, their photon attenuation capability is superior to that of various commercial shielding glasses in fast-neutron nuclear applications at 1°–10³ MeV. In addition, compared to the borate glass systems studied in the literature, B₂O₃-MnO₂-CdO glasses have fast neutron removal cross-sections of 0.125 cm⁻¹ at a smaller density of 3.9043–4.8135 g/cm³, making them potentially excellent fast neutron absorbers.     

Preparation and properties of ferromagnetic glass ceramics and glass fibers based on the composition of SiO2-B2O3-Fe2O3-SrO

The ferromagnetic glass ceramics in the system SiO₂-B₂O₃-Fe₂O₃-SrO were prepared via four different fabrication methods, i.e., fiber-drawing, melt-quenching, natural-cooling, and annealing, without performing any nucleation and crystallization heat treatments. The influences of chemical composition and fabrication method on the spontaneous crystallization of magnetite were investigated by X-ray diffraction, scanning and transmission electron microscopy. The X-ray diffraction patterns show the presence of nanometric magnetite crystals in the glass matrix, and the increasing boron oxide can promote the spontaneous crystallization of magnetite. The estimated size of crystallized magnetite varies between 12 and 50 nm. The magnetic properties of the glass ceramics derived from the four fabrication methods were analyzed using a Vibrating sample magnetometer (VSM), Agilent HP8722ES vector network analyzer and Mössbauer spectra. We find that both the saturation magnetization (M_S) and coercivity (H_jc) depend on the chemical composition and fabrication method. The calorimetric measurements were carried out using Orton Standard Dilatometers.     

Na2O-Al2O3-B2O3系统低熔点玻璃的热学性质研究

介绍了Na2O-Al2O3-B2O3系统玻璃的制备，确定了Na2O-Al2O3-B2O3系统玻璃的成玻范围，研究了玻璃的转变温度（Tg）、软化温度（Tf）和热膨胀系数（α），以及玻璃的Tg、Tf、α与玻璃组成的关系。     

Mechanism for broadening and enhancing Nd3+ emission in zinc aluminophosphate laser glass by addition of Bi2O3

Nd³⁺-doped phosphate laser glasses have been attracting much attention and widespread investigation due to their high solubility of rare earth (RE) ions, excellent spectroscopic properties, and large damage threshold. However, the narrow NIR emission bandwidth (less than 30 nm) of these Nd³⁺-doped phosphate glasses limits their further application toward ultrahigh power field and efficient fiber laser in new region. Here, we demonstrate the broadening and enhancing of Nd³⁺ NIR emission in laser glass of zinc aluminophosphate through tuning the glass structure and covalency of Nd-O bond without limiting the radiative properties of Nd³⁺. The maximum bandwidth of 1.05 μm emission is broadened to 50 nm, which is comparable to that of Nd³⁺-doped aluminate laser glasses. Simultaneously, the lifetime of ⁴F_3/2 level is elongated nearly by two times. Structural and optical properties of prepared glasses were discussed systematically to reveal the mechanism. Detailed analysis on optical spectra and glass structure indicates that the bandwidth is affected by not only the covalency of Nd-O but also the compactness of glass structure. Our results could enrich our understanding about the relationship between local glass structure and luminescence behaviors of active centers, and may be helpful in designing new RE-doped laser glass systems.     

Influence of Bi2O3/TiO2, Sb2O3 and Cr2O3 doping on low-voltage varistor ceramics

The influence of the amount of Bi₂O₃ and TiO₂ additions at a TiO₂/Bi₂O₃ ratio of 1, as well as Sb₂O₃ and/or Cr₂O₃ doping, on the microstructural development and electrical properties of varistor ceramics in the ZnO–Bi₂O₃–TiO₂–Co₃O₄–Mn₂O₃ system was investigated. In samples with a low level of Bi₂O₃ and TiO₂ (0·3 mol%) and therefore small amount of liquid phase, exaggerated growth of the ZnO grains results in high microstructural inhomogeneity. Co-doping with Sb₂O₃ significantly changes the phase composition of TiO₂ doped low-voltage varistor ceramics. The Bi₃Zn₂Sb₃O₁₁ type pyrochlore phase forms at the expense of the γ-Bi₂O₃ and Bi₄Ti₃O₁₂ phases and decreases the amount of liquid phase in the early stages of sintering. Already small amounts of Sb₂O₃ and/or Cr₂O₃ added to a TiO₂ doped low-voltage varistor ceramics limit ZnO grain growth and increase the threshold voltage V_T of the samples.     

Influence of additives on the crystallization and thermal conductivity of container glass cullet for foamed glass preparation

Foamed glass preparation is a complex combination of reactions, greatly influenced by the composition of the used glass and often hindered by simultaneous crystallization. The crystallization phenomenon is undesirable in foamed glass production since it decreases the quality of the final product. In this work the influence of different types of additives (foaming agents, flux agents, crystallization inhibitors and nucleating agent) on the crystallization of waste container glass and properties of the sintered samples (density and thermal conductivity) was studied. Results of our study confirmed partial crystallization during sintering stage. We found that waste container glass manifests complex crystallization with the formation of four main crystalline phases, which can be inhibited with the addition of fluxing agents (B₂O₃ and borax). Moreover, here we show that prevention of the crystallization can lead to a significant decrease of the thermal conductivity.     

Study on the leaching behavior of salt waste forms prepared by using zeolite and lime glass

When the reaction of salt and zeolite was used to minimize the free salt in waste forms (r = 0.1), Cs showed the lowest leaching rate, 1.015 × 10⁻¹ g/m² d. Because alkali chloride is chemically stable, the reaction that alkali elements become components of glass does not happen and thus the leach resistance of the waste form solidified with soda glass was not much different from that solidified with borosilicate glass. The crystalline phase containing Cl was sodalite, but the tendency that Cs exists prior to sodalite phase was not confirmed. From a result of a long-term leaching, the predicted leaching fraction of Cs in 900 days was as high as 5.13%, but that of Sr was as low as 0.24%. The leaching experiment with a varying pH showed the major nuclides such as Cs, Sr, and Li in salt waste had different leaching characteristics each other.     

P2O5对Bi2O3-B2O3-ZnO体系玻璃结构及热性能的影响

采用传统的熔融冷却的方法制备了(40-x)Bi2O3-30B2O3-30ZnO-xP2O5(0≤x≤15mo1％)体系玻璃.使用红外光谱、拉曼光谱、DSC和热膨胀仪研究了封接玻璃的结构和热性能.红外光谱及拉曼光谱结果表明,P2O5作为网络形成体,以[PO4]进入到玻璃的网络结构中,玻璃的网络结构性增强.玻璃结构中[BO3]三角体结构单元相对含量有增多趋势,[BO4]四面体、[BiO3]三角体、[BiO6]八面体结构单元相对含量减少.随着P2 O5含量的增加,玻璃化转变温度和玻璃的初始析晶温度升高;玻璃的密度减小.Bi2O3-B2O3-ZnO-P2O5体系封接玻璃热膨胀系数减小,从8.289×10-6℃-1减小到6.354×10-6℃-1.玻璃的软化点逐渐增大,从416℃升高到524℃.     

废砖加入量对再生Al2 O3 -MgO-C砖性能的影响

将废弃的铝镁碳砖破碎成3~1mm、<1mm和<0.076mm的颗粒,加入<1mm的尖晶石、<0.076mm的特级矾土、<1mm的刚玉和<0.088mm的电熔镁砂等原料混合后,于1500℃下埋炭保温3h烧制成钢包用铝镁碳砖。研究了废砖加入量(w)分别为50%、60%、70%、75%和85%时对其性能的影响,并借助于XRD对材料的物相组成进行了分析。结果表明:废砖加入量对其性能有显著的影响,当废砖加入量为50%时,试样的体积密度最大,为2.76g.cm-3,显气孔率最小,为7.8%;当废砖加入量为70%时,材料的抗折强度和耐压强度都达到了最大值,分别为19.3MPa和78.7MPa;当废砖加入量为85%时,材料的抗氧化性能最差,而材料的抗渣侵蚀性能最好。