Vol 73, No 5-6 (2016)

Ascientifically substantiated applied method of performing engineering calculations of the thermal resistance of the wall layer has been developed. This procedure makes it possible to take account of additional factors—temperature of the melt and composition of the molten glass in the melting tank — and make more accurate predictions of the temperature in corrosion-active zones of the refractory barriers of glassmaking furnaces.

Laser glass was synthesized using a phosphate base with different Nd³⁺ concentrations, whose composition ensures high glassmaking properties and the possibility of obtaining in small crucibles optically uniform glass. The basic spectral-luminescence characteristics of the obtained glasses are determined and it is shown that this matrix ensures long duration of luminescence and high quantum yield in a wider range of Nd³⁺ concentrations. Taking account of the good melting and pouring properties this matrix composition is helpful for development work on new laser materials with a modified luminescence band owing to activation by different rare-earth elements and modification of the matrix by highly polarizable cations.

Subjecting the polished surfaces of optical parts fabricated from silicate glass to treatment in vapors of hexamethyldisilazane results in the formation of a protective film that impedes the action of the ambient environment. Increasing humidity and temperature of the ambient environment diminish the protective properties of the film.

The possible defects and nonconformities with respect to the requirements of artistic-commercial articles made of glass during glass fusion are examined and methods are proposed for eliminating defects and ways to restore rejected articles. An algorithm is developed for taking action when different forms of defects are found in artistic-commercial articles and for determining the desirability of restoration.

It is shown for investigations of casting ceramics that the values of certain characteristics of ceramic materials can be calculated on the basis of the values of the basic characteristics of the initial raw materials: disperse composition, specific surface, type of binder, and chemical composition of the ceramic. Appropriate regression equations for calculating the characteristics required to obtain casting ceramics with prescribed properties are derived.

The problems of enrichment of dolomite, which is used in the preparation of glass batch, are examined. A design of a production line for processing lump dolomite that includes equipment for drying, crushing, and three-step separation of the comminuted material is presented. It is shown that additional reduction of the amount of the dusty fraction of dolomite present in the finished product is possible by means of aero-classification.

Special heat-shielding materials cover the outer surfaces of space shuttles. These materials must also be protected from erosion, moisture, and so forth by thermal control coatings. A series of works was conducted at VIAM on the development and improvement of erosion-resistant thermal control coatings and their manufacture and usage technologies.

Comparative studies of the impregnability of high-strength and basalt fibers, treated and untreated by emulsions of film-formers, by epoxy binders with different curing agents were conducted. Differences in the surface treatment of high-strength and basalt fibers were found by determining the impregnation along the height of capillary rise of the binder. The effect of surface treatment on the change in strength of the tested filaments and microplastics based on them was determined.

The thermal behavior of potassium polytitanate modified in a water solution of CrCl₃ in 4 and 18 h and characterized by different degree of uniformity of the chromium distribution in the particles is investigated. It is shown that even though the powder precursors have close chemical compositions their heat treatment (at 850°C for 2 h) leads to the formation of ceramic nanopowders with different phase compositions. It is shown by means of impedance spectroscopy that the product obtained on the basis the precursor powder with lower uniformity of the chromium distribution has much higher permittivity.

The possibility of synthesizing heat-insulation construction materials with prescribed density on the basis of cullet, slag from a metallurgical plant, and ash-slag wastes from thermal power plants (TPP) is examined. The effect of the type and amount of pore-formers on the structure and properties of cellular glass heat-insulation construction material is analyzed. The compositions, technological parameters, and temperature – time regimes are worked out for the synthesis of tiles, construction – heat-insulation blocks, and porous fillers from cellular glass based on technogenic raw material for light-weight concretes.