Glass Formation and Properties in the System Calcia-Gallia-Silica

The glass-formation region of the calcia-gallia-silica system was determined. The glasses within this region were measured to have a density of 3 to 4 g/cm³, a refractive index of 1.6 to 1.73, an Abbe number between 35 and 58, a thermal expansion coefficient of 6.5 × 10⁻⁷/°C to 11.5 × 10⁻⁷/°C, softening temperatures between 730° and 790°C, and a Vickers microhardness of 5.2 to 7.3 GPa. Crystalline phases were identified along the glass-formation boundary. Infrared transmission spectra were used to explain glass structures and their effect on glass properties. The results suggest that the role of calcia in the glass structure is similar to that for calcia in calcium aluminosilicate glasses.     

Glass Properties in the Yttria-Alumina-Silica System

The glass formation region in the yttria-alumina-silica system was investigated. Properties of glasses containing 25 to 55 wt% yttria were measured and the effect of the composition was determined. The density, refractive index, thermal-expansion coefficient, and microhardness increased with increasing yttria content. The dissolution rate in IN HCl increased with increasing yttria content and temperature. These glasses were also found to have high electrical resistivity.     

Glass Formation and Physicochemical Properties of Alloys in the Cu–Te–I System

The glass formation and the physicochemical properties of alloys in the Cu–Te–I system are investigated. Consideration is given to the glass formation region in the Cu–Te–I system, the results of differential thermal and X-ray powder diffraction analyses, and the temperature dependence of the molar volume for melts. The phase diagram is constructed along the CuI–Te join passing throughout the glass formation region. The inference is drawn that the formation of the CuTeI and CuTe₂I chemical compounds favors extension of the glass formation region in the system under investigation.     

Formation and Properties of a Lead-Barium-Aluminum Phosphate Glass

A lead-barium-aluminum phosphate glass has been prepared by a wet chemical process. The phosphate glass exhibits high transmission in the visible region of the spectrum and into the mid-infrared and can strongly absorb in the ultraviolet at wavelengths of less than 344 nm. In addition, the glass has a relatively high index of refraction and a good chemical durability. Therefore, the phosphate glass can be used for general-purpose optical applications.     

Phase Relations and Glass Formation in the System PbO-GeO,

Phase relations in the system PbO-GeO₂ were determined using the quenching technique. The five compounds detected were: 4PbO-GeO₂, 3PbO-2GeO₂, PbO-GeO₂, and PbO-4GeO₂. The 3:2 and 1:1 compounds melt congruently at 744° and 799°, respectively. The 4:1 compound melts incongruently at 726°C to PbO plus liquid, whereas the 1:4 compound melts incongruently to GeO₂ plus liquid at 790°C. The 1:2 compound has a temperature range of stability between 707° and 730°. The data indicate that no liquid immiscibility gap exists in the system. Indices of refraction for glasses in the system were compared with lead silicate glasses. An addition of ∼65%PbO to GeO₂ is required to prepare a glass with an index near 2.0 whereas with SiO₂, ∼85% PbO is required. It appears that the lead germanate glasses have higher indices than all other two-component oxide glasses. The addition of PbO to GeO₂ decreases the rutile-to-quartz transformation temperature from 1000°C for pure GeO₂ to 990°C. Infrared spectra of lead germanate glasses (∼60w% PbO) show that transmission is good up to 5.5μ but decreases drastically between 5.5 and 6.5μ.     

Glass Formation in the PbO–GeO 2 System

The glass-forming region in the PbO–GeO2 system is studied. To increase the glass-forming limit in this system, the tempering rate of the samples has to be increased using special methodological practices. The dependence of the temperature of the synthesis of lead germanate glass on the PbO content is obtained. It is shown that the corrosion of alumina crucibles proceeded during the synthesis of lead germanate glass. The dependence of the thickness of the corroded layer of the alumina crucible wall on the time of the synthesis of the glass of the 55PbO · 45GeO2 composition, mol % at 900°С is obtained. It is proved that the obtained glass is X-ray amorphous within the whole range of compositions in the PbO–GeO2 system.     

Glass Formation

The ability to form a glass, i.e., the ability to form bonds which lead to a vitreous network, appears periodically in the classification chart of the elements. Thus simple glasses containing only one kind of atom are formed by the elements of Group VI of the periodic table (O, S, Se, and Te). Only these elements are known to form monatomic (primary) glasses and they retain the ability to form a vitreous network when mixed or chemically bound to each other. The elements of Group VI also form binary glasses, i.e., glasses containing two kinds of atoms, with the elements of Groups III, IV, and V. Experimental evidence of the glassforming capacities of these elements and compounds is given; about twenty new glasses suggested by the foregoing were prepared in the author's laboratory. Binary glasses are also known to exist composed of an element of Group VII (F, Cl, I, or Br) and an element of one of Groups II, III, and IV or a transition element. Experimental evidence for these glasses is presented.     

Glass Formation, Properties and Structure of Soda–Yttria–Silica Glasses

The glass-formation region of the soda–yttria–silica system was determined. The glasses within this region were measured to have a density of 2.4 to 3.1 g/cm³, a refractive index of 1.50 to 1.60, Vickers hardness values of 3.7 to 5.8 GPa, softening temperature between 500° and 780°C, and a coefficient of thermal expansion of 7 × 10^-6/oC to 19 × 10^-6/o C. Aqueous chemical durability measurements were made on select glass compositions while infrared transmission spectra were used to investigate the glass structure and its effect on glass properties. A compositional region was identified which exhibited high thermal expansion, high softening temperatures, and good chemical durability.     

Formation and Properties of a Novel Heavy-Metal Chalcogenide Glass Doped with a High Dysprosium Concentration

A novel heavy-metal chalcogenide glass doped with a high dysprosium ion (Dy³⁺) concentration was prepared by the well-established melt–quenching technique from high-purity elements. The results show that when Cadmium (Cd) is introduced into chalcogenide glass, the concentration of Dy³⁺ ions doped in GeGaCdS glasses is markedly increased, the thermodynamic performance improves, and the difference between T _g and T _x is >120°C. The Vickers microhardness is also modified greatly, about 245 kgf/mm². The optical spectra indicate that all absorption and emission bands of Dy³⁺ are clearly observed and red-shifted with increasing Dy³⁺ concentration.     

Numerical Modeling of Glass Formation Process in an Advanced Glass Melter

In the advanced glass melter glass batch materials are entrained in gas and then rapidly heated to glass formation temperature by combusting the gas. The glass batch separates on a target where glass formation takes place. A numerical model has been developed to simulate this glass formation process, which differs from the conventional glass formation process because the batch materials are mixed at glass formation temperatures and because the calcination of Na₂CO₃, CaCO₃, and MgCO₃ occurs on the surface of the glass layer, not in the bulk material. The numerical model is based on diffusion-controlled dissolution of sand particles in the liquid glass. Preliminary experimental data support the rapid glass formation rates predicted by the numerical model.     

Li2O-ZnO-SiO2系微晶玻璃结构和性能的研究

介绍了利用传统熔体冷却方法制得以P2O5为晶核剂的Li2O-ZnO-SiO2系玻璃,并探索了该系统微晶玻璃的制备工艺,用XRD、SEM和FT-IR以及膨胀系数测定仪对微晶玻璃的结构和性能进行了研究,表明了该微晶玻璃可望作为镍、镍合金及1010钢等金属的封接材料.     

Oxynitride Glass Formation from Gels

Porous, multicomponent silicate gels were heated in flowing and pressurized ammonia. These treatments resulted in dense, homogeneous oxynitride (O-N) glasses which were synthesized at low temperature (∼1000°C) without melting. The O-N glasses exhibited increased microhardness and glass-transition temperature and altered thermal expansion characteristics compared to the respective oxide glasses prepared by densi-fying gels in air or by conventional melting of oxide powders. Spectroscopic evidence indicates that ammonia reacts with all of the network-formers investigated, Si, Al, and B, hut from nitrogen content measurements, it appears that B and/or Al are required for significant nitridation below 1000°C.