Nanocrystalline powders of LiZnMn ferrite were obtained by the method of solution combustion at various glycine-nitrate ratios (G / N = 0.2, 0.4, ..., 1.4). Elemental analysis showed that the composition of the obtained samples corresponds to the spinel ferrite Li 0.45 Zn 0.05 Mn 0.06 Fe 2 , 43 O 4 . Based on the SEM results, it was found that the compositions have a porous microstructure and a developed surface, and the X-ray phase analysis data indicate that the synthesized LiZnMnFe spinel is single-phase and has a high degree of crystallinity (up to 99 & # 37;). It is shown that the magnetic and dielectric characteristics of the obtained samples change systematically depending on the selected redox ratio of the reaction mixture and reach maximum values ??at a stoichiometric value of G / N = 0.6
A porous, catalytically active membrane based on coarse silicon carbide has been synthesized. To synthesize the membrane, ultradispersed additives of the eutectic composition of magnesium oxide and silicon carbide were introduced into the initial SiC powder, which, during sintering at temperatures in the range from 1100 to 1450 & # 176; C, form a liquid phase in the form of clinoenstatite MgSiO 3 , which wets the coarse SiC particles and forms a porous strong membrane framework. The dependence of the pore size of the ceramic material on the pressing pressure was investigated, which made it possible to obtain a highly porous ceramic membrane with pores of the most optimal size for the dehydrogenation of ethylbenzene to styrene. To give the synthesized membrane the catalytic properties required for the dehydrogenation process, the pore surface is modified to 10 & # 37; Re & ndash; W active ingredients using the alkox method
The influence of underglaze paints in the form of solutions of cobalt and nickel salts on the formation of the structure of a porcelain article, especially in the zone of contact between porcelain and glaze, has been established. In this zone, salts change the character and size of crystalline neoplasms. Cobalt ions form compounds that are more soluble in the glass phase of porcelain and glaze than nickel ions, as evidenced by the color of the glassy layer of the glaze. With increasing salt content, a crystalline paint layer forms on both sides of the product.
The results of studying the morphology and optical properties of copper and fluorine-doped ceramic TiO 2 films synthesized using electrolytic and solvothermal methods are presented. It is shown that the films obtained consist of oriented arrays of nanotubes with anatase crystal structure, narrow size distribution, and a high degree of hexagonal self-organization. The influence of the conditions of the solvothermal process on the composition, morphology, structure, and optical properties of the materials obtained has been established.
Obtained porcelain stoneware based on Russian raw materials at a relatively low temperature in the range of 1200 & ndash; 1250 & # 176; C. X-ray phase, IR spectroscopic and electron microscopic analyzes showed the presence of quartz, cristobalite, mullite and glass phase in porcelain stoneware, and the content of the latter is not less than 50 & # 37 ;. High physical and mechanical properties: strength, frost resistance, heat resistance, etc. & ndash; porcelain stoneware gives mullite
The results of studies on the use of fluorides of sodium fluoride NaF and sodium tetraborate (borax), as well as their mixtures in the synthesis of foam glass materials based on diatomite raw materials according to & # 171; hydrated & # 187; are presented. mechanism using an alkali solution. The influence of NaF and borax on the process of formation of the structure of the material and the mechanism of their action during heat treatment have been investigated. The optimal ratios of the charge components and the temperature-time regimes for the synthesis of foam glass materials with the use of these additives as materials intensifying the sintering and melting processes have been established.
Ceramics in the Ca 2 P 2 O 7 -Ca (PO 3 ) 2 was obtained by firing a cement stone made from a powder mixture containing ?-tricalcium phosphate ?-Ca 3 (PO 4 ) 2 and monocalcium phosphate monohydrate Ca (H 2 PO 4 ) 2 & middot; Н 2 O. The Ca / P molar ratio of the starting powder mixtures was set to Ca / P & lt; 1. According to XRD data, all ceramic samples after firing at 1000 ° C included ?-calcium pyrophosphate ?-Ca 2 P 2 O 7 , and a ceramic sample from a powder mixture with a maximum content of monocalcium phosphate monohydrate Ca (H 2 PO 4 ) 2 & middot; H 2 O contained also ?-calcium polyphosphate ?-Ca (PO 3 ) 2 . The resulting calcium phosphate ceramics with a low firing temperature can be used to create a resorbable base for tissue engineering structures.
The microstructure and phase transformations of copper-doped BiNbO 4 ceramics synthesized at 950 and 1100 & # 176; C are investigated. According to XRD data, samples in a compact, pressed form crystallize in the ?-BiNbO 4 structure, regardless of the synthesis temperature and in spite of the phase transition ?. & # 8594; ? at 1040 & # 176; С. BiNb 1 & ndash; x O 4 & delta; xCuO (x & le; 0.04) preparations are graphite-colored composites with a visually pronounced grain microstructure. The thermograms of the samples show an endothermic effect near 900 ° C, associated with the decomposition of copper (II) oxide, and heat effects due to the occurrence of reconstructive phase transformations in BiNbO 4 of the ?; & # 8594; .gamma; & # 8594; ?. It was found that an impurity of copper oxide in the ceramics of bismuth orthoniobate acts as a heat sink, which leads to an increase in the phase transformation temperature .alpha. & # 8594; .gamma; when heating compact samples
The phosphate ore of the Polpinsky deposit contains up to 30 & # 37; silica. In the process of direct acidic processing of phosphorite into mineral fertilizers, silica is a ballast, which is advisable to be removed from the composition of the product. The possibility of using silica as a raw material for the glass industry was substantiated, for which its phase and chemical compositions were established and compared with the current technical conditions.
The chemical, phase composition and properties of metallurgical dust have been studied, and its structure and particle size distribution have been determined. The physical & ndash; chemical processes occurring during heat treatment of dust in the temperature range 20 & ndash; 1200 & # 176; C. On the basis of the studies carried out, the main directions of processing the studied dust in order to obtain useful products are proposed.
