Papers by Keyword: Borosilicate

Abstract: The borosilicate glass samples doped with NiO have been fabricated by conventional glass making process and changed the composition of chemicals. Rice husk ash (RHA) was used as a SiO₂ source for prepare the glass samples. The physical and optical properties, viz., glass density, molar volume, refractive index and absorption spectra have been studied. The results show the density increased with increasing of NiO amount due to the difference of atomic weight of Si and Ni. The molar volume obtained from the density of glass, depends on changed rates of density and atomic weight. Those values increased when the amount of NiO increase due to the increasing in bond length between atoms. Moreover, the refractive index increased with increasing concentration of NiO.

Abstract: In this work, glasses with compositions, close to commercial borosilicate glasses, were developed. The main raw materials were residues of ornamental rock industries ( marbles and granites ). Beach sand was used in order to enrich the compositions with silica. Also, boron oxide was added to reach borosilicate glasses compositions. The obtained glasses were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), and hydrolytic resistance. The measured properties were compared to those of commercial glasses, available in the market, from two different brands. XRD results confirmed amorphous patterns of the produced glasses. The other tests revealed an excellent agreement between the obtained values and those from commercial glasses. Therefore, this study showed the possibility of using ornamental rocks residues as primary sources to produce borosilicate glasses. In addition, it became clear that an economic value could be aggregated to the residues, which otherwise would be discharged into nature causing pollution.

Abstract: As a naturally-occurring trace element, boron involves many life processes including embryogenesis, bone growth and maintenance, immune function and psychomotor skills. Thus, the low chemical durable glass based on 3-fold coordination boron network former shows potential in delivering boron for bone health. However, its high dissolution rate may result in cytotoxicity. The addition of strontium seems to be an effective approach not only inhibits its rapid degradation, but delivers strontium as a ‘drug’ to enhance the ability of bone formation. Thus, strontium-incorporated borosilicate shows special role in bone regeneration, in particular in women past menopause.

Abstract: Isothermal oxidation behavior of Al added Mo-Si-B in-situ composites was investigated under Ar-20%O2 and air atmosphere over the temperature range of 1073–1673 K. The Al added Mo-Si-B composites ((Mo-8.7mol%Si-17.4mol%B)-1mol%Al) were prepared by arc-melting, and homogenized at 2073 K for 24 h in an Ar-flow atmosphere. The ternary Mo-Si-B in-situ composite exhibited a rapid mass loss at the initial oxidation stage and then the passive oxidation after the substrates were sealed with borosilicate glass in the temperature range of 1173–1473 K, whereas it exhibited a rapid mass gain around 1073 K. On the other hand, the Al addition significantly improved the oxidation resistance of Mo-Si-B in-situ composites at temperatures from 1073–1573 K. These excellent oxidation resistances are considered to be due to the rapid formation of a continuous, dense scale of Al-Si-O complex oxides.

Abstract: Al2O3 and TiO2 were sintered with three types (lead, zinc, bismuth) of borosilicate glass. Their microwave dielectric properties and sintering behavior were investigated as functions of glass type, glass addition (10~50 vol%) and sintering temperature (600~950°C for 2 hrs). Sintering characteristics were well described in terms of softening temperature, second phase, and excessive liquid. In particular, Bi2O3 addition to the glass enhanced reaction with Al2O3 and TiO2 to form liquid phase and second phase. In terms of dielectric properties glass/Al2O3 composites for application to substrates while glass/TiO2 composites for filters were shown to be appropriate.

Abstract: Knowledge on diffusion of water in glasses and melts is important for glass sciences as well as for Earth sciences. The ranges of water contents differ widely in both research domains. Industrial glass contain typically less than 0.1 wt% H2O whereas natural glasses may even contain up to 10 wt% H2O. Dissolved water strongly modifies physical and chemical properties of the melts and, hence, water diffusion studies at low water contents often cannot be transferred to high water contents and vice versa. Pressure effect on water diffusion, on the other hand, is small so that high pressure data can be applied also at ambient pressure without significant error. At low water contents the assumption of constant water diffusivity is often justified whereas at high water contents the H2O diffusivity increases strongly (often linearly or exponentially) with water content. Combining experimental data over a wide range of water contents allows getting deeper understanding of the mechanisms of water diffusion and of the effect of dissolved water on melt structure. In this paper an overview is given on experimental investigations on water diffusivity in aluminosilicate and silicate systems. Effects of base compositions and water content on water diffusivities are discussed. New experimental results for water diffusion in soda lime silica glass, float glass and borosilicate glass are presented.