Papers by Keyword: Borosilicate Glass

Abstract: Photosensitive glass-ceramics have been extensively studied in recent years in that it is an attractive high diffraction efficiency grating materials. It is based on Stookey’s mixed fluoride sodium glass system for us to adopt, design prescriptions on the basis of SiO₂-Na₂O-Al₂O₃-ZnO for the glass main component and a series of glass doped with CeO₂, AgNO₃ and NaF etc. melted at about 1450 °C, and the glass have good optical property (homogeneity, without bubble and stripe, high transparency). The borosilicate glass was exposed by ultraviolet light, and then after the heat treatment of the sample, the measurement of ultraviolet-visible-near infrared absorption spectrum and the X ray diffraction of exposure part was performed.

Abstract: Physical and mechanical behaviour of cement pastes with partial Portland cement replacement by fine milled waste glass is researched in the presented paper. The tested pastes contain milled borosilicate glass in amount of 5, 10, 20, and 30 mass% of cement. The chemical composition of borosilicate glass and used Portland cement is accessed by XRF (X-Ray Fluorescence) analysis. For the milled glass, pozzolanic activity and particle size distribution are measured. Here, modified Chapelle test is used for evaluation of pozzolanic activity. Particle size distribution is measured on laser diffraction principle. Basic physical properties and mechanical properties are determined for samples cured 28 and 90 days in water in order to evaluate the kinetics of hydration process. The obtained results revealed the possible applicability of the tested borosilicate glass in the composition of cement-based composite materials.

Abstract: This Borosilicate glass offers superior properties to the ordinary silicate glass. Metallic quantum dots embedded in glass are promising materials which can be used in modern optical devices. However, the introduction of metallic quantum dots into borosilicate glass has not been studied. We investigated the formation of copper quantum dots in Cu-doped borosilicate glass matrix using thermal annealing process. The reductant SnO included in borosilicate glass played an important role in the formation of the metallic quantum dots. Specifically, Cu quantum dots were formed only when SnO content reached at least 0.5 wt% after borosilicate glass was heated at 600 °C for 60min, which was evidenced by the detection of the characteristic absorption band at about 560nm originated from the surface plasmon resonance of Cu nanoparticles. The optimal concentration of SnO was found to be 1.5 wt% and the mean size for the heating-induced Cu quantum dots was calculated to be ~1.7 nm. Our data offer a simple approach to prepare the metallic quantum dots in borosilicate glass matrix and suggest a new type of metallic quantum dots for applications where superior durability, chemical and heat resistance are required.

Abstract: According to analyze service condition and extent of damage of cordierite bricks used in coke oven, the experiment was prepared by using spodumene powder, cordierite powder and fused silica as main starting materials, borax as the flux. The effect of borax on melting properties and thermal shock resistance of low-temperature glaze used in coke oven cordierite brick was investigated. The results showed that the melting temperature of glaze is close to the theoretical calculation, Seger formula can be equally applied to metallurgical industry. With the amount of borax increasing, the melting temperature of the glaze reduced. When the amount increased to 22%, borax dissolved in the mullite phase, which increased the content of glass phase in glaze. When the temperature is 1000°C, glaze layer formed and spreaded evenly on the surface of cordierite lining bricks and didn’t flowing. After five thermal shock, glazed surface didn’t appear crack, the requirements were achieved that glaze can be generated in the carbonization chamber temperature of coke oven without pre-firing. When the amount of borax continues to increase, the viscosity of glaze decreases, which results in flowing.

Abstract: We demonstrate the vertically well-aligned zinc oxide (ZnO) nanowires synthesized on amorphous borosilicate glass (BSG) via simple chemical vapor deposition (CVD) process with a vapor trapping approach. During the process, zinc precursor was put inside a glass vial with the vial’s opening was directed towards the BSG substrate, which is being placed downstream from the gas flow and approximately 30-40 mm from the precursor. The BSG substrates were coated with Nichrome (NiCr) and gold (Au) coating prior to the synthesis process. Vertically aligned nanowires with a high aspect ratio was found to be deposited in total operating pressure of 20-25 bar with an Oxygen flow rate range of 5-10 sccm and argon flow rate range of 30-50 sccm. This vapor trapping approach using BSG substrates provided a good alternative towards controllable growth of ZnO NWs on any much cheaper amorphous substrates for future development of low cost energy-converter heat cell devices based on ZnO nanowires.

Abstract: We demonstrated a model to realize the growth of indium-silver alloy nanocrystals in borosilicate glass by sol-gel method. The presence of spherical indium-silver alloy nanoparticles with 5 nm average grain size and finely dispersed form in borosilicate glass was confirmed by transmission electron microscopy imaging. Reduction of indium-silver ions to indium-silver alloy neutral nanoparticles was revealed through X-ray powder diffraction and X-ray photoelectron spectra. Remarkably, Indium-silver alloy nanocrystal-borosilicate glass exhibited fluorescence at around 423 nm.

Abstract: Hollow glass microspheres (HGMs) are a unique class of materials with interconnected pores in the microsphere walls, which can adsorb, retain and release hydrogen and other gases. In this study, HGMs was prepared from amber coloured and borosilicate glass frits. The glass frits after the preliminary washing and drying was sized to particles below 120 μm. The hollow glass microspheres were successfully fabricated from the glass powder by flame spheroidisation using air-acetylene flame. Effect of glass feed particle size as well as feed rate, in the formation of HGMs was studied. Glass feed particle size >75 μm and that <45 μm were found to give very poor yield of HGMs, whereas particles 50-75 μm gave very good yield for HGMs. Further study of the process parameters and constant monitoring to regulate the process are being carried out in our laboratory to arrive at a correct figure for the yield of HGMs. Characterisation of the HGMs prepared was done using Image analysing system, SEM, and XRD. The composition of the raw material and the product HGMs were determined using ICP-AES.

Abstract: The effects of silicon dioxide addition on the sintering, microstructure and microwave dielectric properties of Ca-Al-B-Si-O glass/Al₂O₃ composites were investigated. Results show that: Increasing the silicon dioxide content in the glass leads to the corresponding rise of bulk density, dielectric constant of the LTCC materials and the decrease of its dielectric loss and porosity. A bulk density of 2.92 g·cm^-3, a porosity of 0.2%, aε_r value of 7.11 and a tan δ value of 0.00096(measured at 10 MHz) are obtained for 68 wt% silicon dioxide of the samples sintered at 875°C for 30 min.

Abstract: Oxidization of diamond in the sintering process of diamond/borosilicate glass composites would result in low compressive fracture strength (CFS) of the grit and uncontrolled expansion with many irregular pores in the composites, causing low bending strength of the tools. In this paper diamond/borosilicate glass composites were prepared by cold pressing and sintering at 850 C for 120 min in air. An active element Zn was incorporated into the composites in order to resolve the above issues. The effects of Zn contents on the properties of the composites was investigated by the bending strength tests, the volume expansion rate tests, differential scanning calorimeter test (DSC), thermogravimetry (TG), X-ray diffraction analysis (XRD), and scanning electron microscope (SEM). The results showed Zn was oxidized and then converted to ZnAl2O4 and Zn2SiO4 phases during sintering. The bending strength improved and the expansion phenomenon was inhibited for the composites with various Zn additions. The maximum bending strength and minimum volume expansion rate were obtained for the composite GZ8. This Zn content resulted in a decrease of volume expansion rate from 8.57% to -20.53%, and an increase in bending strength from 28.49 MPa to 74.02 MPa compared with the composite GZ0. The CFS results of the diamond grits separated from GZ0 and GZ8 was 21N and 26N, respectively.

Abstract: We present the preparation, structural, and magnetic properties of a series of Fe-containing borosilicate glasses as a function of the ratio SiO2/Fe2O3 which is ranging from 1.49 to 2.68. The role of nucleators (Cr2O3 and P2O5) was also investigated. X-Ray diffraction has revealed the formation of magnetite as the major or unique crystalline phase. As SEM micrographs have revealed, the addition of P2O5 give rise to a finer structure as compared with Cr2O3. In addition, the same oxide decreases the temperature of structural transition with almost 100 °C. The magnetization data reveal a two step transition at low temperatures: a high temperature transition at Tv = 128 K, which we attribute to the Verwey transition, and a low temperature transition at Ts = 48 K which, most likely, is the result of change in the dynamic of the domain motion.