Analytical and empirical dependences for calculating the thermal homogeneity index of molten glass in the feeder channel of glass-forming machines are presented. The analytical dependences were tested for 9- and 5-point temperature matrix
The technological parameters for the synthesis of an optically transparent glass-crystalline material based on lithium silicate glass under the conditions of a two-stage low-temperature short-term heat treatment have been developed. It has been established that such a material, characterized by high mechanical properties, heat resistance and light transmission 72 & # 37;, is promising in the development of transparent sitalls for the protection of optical devices of special equipment.
A review of technologies for laser welding of glass is carried out. The technologies of welding with continuous CO 2 -laser radiation in the mode of surface heating and in the mode of deep penetration are presented. The technology of glass microwelding by lasers with ultrashort pulses and high pulse repetition rate is considered.
The phase composition, structure and distribution of elements and hydrolytic stability of quenched and annealed sodium aluminum phosphate (NAF) and sodium aluminum iron phosphate (NAIP) glass materials containing over 100 & # 37; 10 & # 37; (mass content) oxides of rare earth elements (REE). It was shown that all materials obtained by quenching the melts, except for La-containing ones, were X-ray amorphous, while slowly cooled (annealed) materials partially or completely crystallized with the precipitation of various phases of orthophosphates. The leaching rate of elements from annealed NAF glasses, determined at 90 ° C, is approximately 1 - 2 orders of magnitude higher than from tempered ones, and the leaching rates of elements from tempered NAF glasses are lower than from tempered NAF glasses.
A scientifically substantiated applied technique for indirect assessment of the actual intensity of convective heat removal during jet cooling of corrosive zones of the melting basin of glass-making furnaces is presented, which makes it possible to determine the actual heat transfer coefficients in critical zones based on the results of direct measurements carried out within the framework of current monitoring of the state of refractory structures of the melting basin of glass-making furnaces. An algorithm for practical implementation is developed and a real example of using the proposed methodology is given.
The compositions of glasses for the manufacture of hollow glass microspheres have been developed. The main physical and technical characteristics have been studied and the dependences of properties on the composition of glasses have been established. The influence of rheological properties of glasses near liquidus temperatures on the processes of release of gases previously dissolved in glass is shown. The possibility of obtaining hollow glass microspheres with a size of 20 - 200 microns has been established.
The analysis of methods for monitoring the stress-strain state of transparent elements for special glazing used in aviation, as well as for inclusion in the composition of transparent armor is presented. The data of control of samples of satellites of chemically hardened glass obtained using a scattered light polariscope and a destructive method of centrally symmetric bending are presented. Based on these data, conclusions were drawn about the possibility of using non-destructive testing methods as indicators of the stress-strain state of the glass surface.
Research has been carried out in the development of a new technology for producing foam glass from materials containing natural amorphous silica. The optimal technological parameters for obtaining products with a given geometric shape and dimensions are shown. The theoretical substantiation of the organization of technological processes is given. The results of studies of the properties of the materials obtained are presented.
The local crystallization of barium-titanosilicate glass under the action of a femtosecond laser beam is investigated. The effect of the laser beam scanning speed and laser pulse energy on the morphology of channels containing Ba 2 TiSi 2 O 8 fresnoite crystals is determined. The preferential orientation of fresnoite crystals in the formed channels has been established by the method of polarization Raman spectroscopy. The results obtained open up prospects for the development and manufacture of waveguide crystal structures with low optical losses for photonics and integrated optics.
The results of the synthesis of antireflection mesoporous coatings based on silicon dioxide obtained by acid hydrolysis of tetraethoxysilane (TEOS) in the presence of organic additives are presented. Investigations of the influence of the acidity of the medium, the nature and mass content of the modifier on the optical properties of the coated glass have been carried out. Optimal synthesis parameters have been determined
