An explanation is proposed for the possibility of the formation of solid solutions of silicon oxide in mullite. The difference in the diffusion coefficients of cations in complex oxides during their synthesis leads to the formation of a solid solution of an oxide containing a cation with a lower diffusion coefficient in a complex oxide and a phase consisting of an oxide containing a cation with a high diffusion coefficient or enriched in this oxide. Using additives of yttrium or scandium oxides, which are chemisorbed onto the aerosil surface (source of SiO 2 ), it is possible to make the rate of diffusion mass transfer of aluminum cations higher than that of silicon cations, and to obtain a solid solution of silicon oxide in mullite. Il. 2, bibliography: 10 titles.
The author's many years of experience in the field of ceramic pressing technology are summarized, which can be used by specialists both for the restoration and improvement of technological processes for the production of ceramics at enterprises, and for improving the quality of products. Il. 2, bibliography: 5 titles.
A technology for the production of gypsum-ceramic material based on fluoroanhydrite has been developed. With the help of methods of physicochemical analysis, its composition and properties are determined. The developed material is ground and polished, does not accumulate static electricity, and has a surface texture similar to marble. Il. 6, bibliography: 2 titles.
Considered are promising unconventional raw materials for the production of aluminosilicate ceramics: porcelain stones, in particular quartz-sericite, kaolin from the Zhuravliny Log deposit, complex additives represented by magnesium-containing minerals (talc, marble, diopside, dolomite). Tab. 1, bibliography: 7 titles.
The composition and microstructure of UV-46 and M-23 electric porcelain are considered, and their basic physicochemical properties necessary for the creation of certain types of insulators intended for operation in a wide temperature range are described. Particular attention is paid to the dielectric properties of porcelain for electrical purposes, methods for their improvement are given. Tab. 3, bibliography: 10 titles.
The sequence of the appearance of the silicon nitride phase in the volume of the initial silicon grain upon heating in a nitrogen gas atmosphere is traced. Technologies for the manufacture of ceramic products based on silicon nitride are proposed. Il. 8, bibliography: 2 titles.
The fundamentals of obtaining highly dispersed powders of oxide materials, including those of complex composition, by the sol-gel method are considered. Various compounds (polyacrylic acid, polyacrylamide, polyvinyl alcohol) were used as a gelling agent in true and colloidal solutions of the main components. When obtaining powders by the sol-gel method, the temperature of synthesis of complex compounds is reduced by 150 - 200 ° C, while the particles are nano-sized. Tab. 5, ill. 1, bibliography: 11 titles.
The processes accompanying the creep of ceramics and refractories are considered. Structural defects according to their effect on creep can be arranged in a row (in order of decreasing impact): macropores; inclusion of low-melting phases, especially the glass phase; micropores; crystal boundaries, especially those passing through micropores; block boundaries; dislocation; vacancies. The sequence in the series is determined by the intensity of diffusion mass transfer, i.e., by the concentration of vacancies near the listed structural elements (defects). Il. 8, bibliography: 22 titles.
The results of a study of the effect of Y 2 O 3 and CaO additives introduced into the charge in the form of oxides and salts on the sintering and properties of ceramics based on AlN are presented. The effect of high-temperature annealing of ceramics in a flow of a mixture of nitrogen and hydrogen on its properties is shown. Tab. 1, ill. 1, bibliography: 1 titles.
The additives used in the technology of corundum ceramics, which form a liquid phase during the firing process, are classified. The basic principles are formulated that must be taken into account when choosing additives that ensure the production of high-quality alumina materials with a low sintering temperature. A number of eutectic systems have been proposed, the introduction of which into corundum allows the production of dense ceramic materials at firing temperatures of 1350 - 1550 ° C. Some features of the sintering of these materials are considered. Tab. 2, bibliography: 14 titles.
