The general provisions and features of the transfer phenomena in glass-forming melts and glass-making furnaces are considered. The interrelation of transport phenomena with physicochemical factors is shown, as well as the role of thermal diffusion phenomena in the formation of colored layers of molten glass. The importance of strict adherence to technological regimes for obtaining high-quality products was noted. Il. 3, bibliography: 8 titles.
The processes occurring during the production of glass fiber from glasses of various chemical compositions, as well as the influence of hydrostatic forces, surface tension forces and internal friction forces on the molding process are considered. The critical temperature of fiber spinning is determined under conditions when the forces of viscosity and surface tension of the glass melt are equal in magnitude. A new approach is proposed for assessing the fiberizing ability of glass in terms of surface tension to viscosity. A calculation method is given for evaluating the speed of forming glass fibers of various diameters by the example of glass E. Some mechanisms of adhesion of organic polymer and protein molecules to the glass surface are given. Tab. 2, bibliography: 7 titles.
The state of the art in the development of low-melting glasses, used, in particular, as fluxes for the production of silicate paints, is analyzed. The results of developments and patent data in this area for the last 30 years are presented. Tab. 3, bibliography: 12 titles.
The EPR and optical absorption spectra of V 4+ ions and their relationship with the structural features of glasses of the La 2 O 3 - Al 2 < / sup> O 3 - SiO 2 . Three characteristic ranges of EPR parameters of V 4+ ions have been established: I - A II & # 8776; 167 x 10 -4 cm -1 , g II = 1.937 - 1.938; II - A II & # 8776; (163 ... 164) x; 10 -4 cm -1 , g II = 1.939 - 1.940; III - A II & # 8776; (156 ... 159) ?; 10 -4 cm -1 , g II = 1.945. It was shown that in the region with a low La 2 O 3 content, lanthanum plays predominantly the role of a modifier ion, while in glasses with a high La 2 O 3 lanthanum gradually takes a place in the glass network, linking silicon-oxygen and alumino-oxygen tetrahedrons, i.e., it becomes a glass former despite the large ionic radius. Glasses in region III with a high La 2 O 3 content have a high softening point and an abnormally high thermal conductivity (& # 8776; 12.6 W / (m * K)) .Table. 2, ill. 6, bibliography: 10 titles.
The effect of small additions of phosphorus oxide on the optical transmission of silicate glasses in the visible and near-IR regions has been studied. It is shown that an increase in the phosphorus concentration is accompanied by an increase in absorption in the IR region, which is due to an increase in the relative content of ferrous iron and its possible transition to octahedral coordination. The increase in absorption in the visible region is insignificant and cannot become an obstacle for doping industrial silicate glasses with phosphorus.
Tab. 1, ill. 2, bibliography: 6 titles.
One of the techniques allowing to limit the excess of the regulated concentrations of oxygen and moisture is the organization of gas exchange in the float bath, which ensures their continuous removal until the permissible concentrations are reached. Such a gas exchange can be organized by continuously feeding a certain amount of a nitrogen-hydrogen protective mixture into the bath, i.e., a certain exchange rate must be observed. A method for determining the frequency of exchange in a float bath is considered, taking into account its sealing, the quantity and quality of the protective mixture supplied to it. Techniques are proposed to ensure the required exchange rate. Tab. 1, ill. 1, bibliography: 9 titles.
The temperature regimes of obtaining glass granulate, which is the initial raw material for glass-ceramic foam materials, are considered, depending on the composition of the charge and the nature of the main glass-forming component. It was found that when heating the charge based on silica and alumina-containing natural materials, they have different behavior. When processing the charge in an industrial conveyor-type furnace, for each charge, it is necessary to select an individual temperature regime in order to obtain a high-quality glass granulate. Tab. 3, ill. 3, bibliography: 2 titles.
On the basis of the principle of superposition of wave addition, a mathematical model of the power distribution on the surface of a glass plate when it is heated with the help of tubular heaters is proposed. Such a model makes it possible to predict the propagation of the temperature field on the surface of the glass plate, depending on the location and power of the heating elements. Il. 4, bibliography: 3 titles.
The structure of multicomponent silicate glasses with additives of phosphorus oxide, simulating the industrial compositions of container and sheet float glass, has been investigated by the methods of IR spectroscopy and Raman scattering of light. It was found that the introduction of Р 2 О 5 leads to the formation of a microheterogeneous structure consisting of silicon-oxygen anionic groups of various degrees of connectivity and orthophosphate groups. This heterogeneity of the structure contributes to the subsequent segregation and crystallization of multicomponent glasses containing phosphorus. Tab. 1, ill. 2, bibliography: 11 titles.
The results of studies of glass-crystalline materials based on cordierite glass containing TiO 2 as a catalyst are presented. It was found that the synthesis of glass under the influence of a concentrated radiant flux has the same effect on crystallization processes as an increase in the catalyst content. The optimal composition and conditions for obtaining sintered sitalls from glass powder have been determined. Il. 3, bibliography: 5 titles.
