VOL 85, No. 10 (2012)

The behavior of water in model glasses of Na ₂ O - B ₂ O ₃ - SiO ₂ systems has been studied by IR spectroscopy. and K ₂ O - B ₂ O ₃ - SiO ₂. It has been established that hydroxyl groups and water in molecular form are present in alkaline borosilicate glasses of these systems, obtained by quenching a water-containing melt. The distribution of water between its forms and the silicate and borate components of the glass structure depends on their chemical composition. The formation of hydroxyl groups involves proton-cation exchange with the participation of non-bridging oxygen atoms coordinated by alkali metal ions.

Fine-dispersed powders of rare-earth elements (REE) aluminates were obtained by the "wet combustion" method. The solid-phase synthesis of lanthanum-gadolinium aluminate has been studied. It has been shown that the target phase can be obtained at temperatures up to 750 ° C. Firing modes have been found that make it possible to obtain ceramics based on rare-earth aluminates with low open porosity and relative density up to 99% of theoretical.

The change in the mass of silicon samples of different initial density, apparent density, ultimate strength, phase composition during nitriding in the nitrogen pressure range of 0.002 - 18 MPa is traced. It is shown that an increase in the reaction rate of nitrogen with silicon occurs up to a nitrogen pressure of 1.5 MPa; at high nitrogen pressures, the growth of the reaction rate slows down. At a firing temperature of 1710 ° C, ceramics with a relative density of 90% and a bending strength of 540 MPa were obtained. Ceramic parts of an internal combustion engine have been manufactured that are operable under the operating conditions of a real engine.

The results of the study of the possibility of synthesizing pigments based on mervenite are presented, methods of directed regulation of the processes of structure and phase formation for the synthesis of pigments with high physicochemical properties have been developed, the relationship between the temperature and time parameters of synthesis, the content of introduced oxides-chromophores and the type and amount of forming color-bearing phases has been established. providing rich color and a wide range of pigments.

Changes in the phase and chemical compositions, as well as the course of hardening during heating of mixtures with a phosphate binder of pyrophyllite raw materials from the Kul-Yurt-Tau deposit and for comparison of raw materials from the Ovruch deposit, have been investigated. It is shown that the behavior of these materials is similar. The optimal amount of binder has been determined to obtain a durable pressed semi-finished product. To achieve water resistance and the required strength of composites, they should be processed at temperatures of 500 - 600 ° C.

It has been established that the evolution of the structure of the solid phase of the material and the porous structure proceeds mainly in different directions: if, with a decrease in porosity, the coordination number in the solid phase of the material increases, then in the porous structure it decreases. A universal fairly rigorous model of the structure of highly porous and low-porous ceramic materials obtained by pressing and using powdered burnable monodisperse additives is proposed.

Nanoporous ceramics with a pore volume of about 60% were obtained by isostatic pressing from Al ₂ O ₃ nanopowder. The study of the microstructure, porosity and strength of the obtained ceramics has been carried out. The technological conditions for the production of nanoporous ceramics, which provide an optimal combination of strength and porosity, have been determined.

An assessment of the antibacterial effect of special glass enamel coatings, developed to protect parts of water heating equipment, is given. The effectiveness of coatings with a bactericidal agent in relation to microorganisms E. Cloacae and E. Coli is shown.

The features of thermally activated pore formation of zeolite-containing rocks (CP) and flask in alkaline compositions are considered. It has been established that the low-temperature pore-forming gas phase in the flask + NaOH and CP + NaOH systems is water vapor formed during the dehydration of hydrated sodium silicates. In the mass of CP + NaOH, the second, higher-temperature source of water vapor is a hydrated silicate surface of amorphized post-zeolite components.