The processes occurring in the plasma-chemical synthesis of melts from silicate-containing materials, as well as technological modes in the production of silicate refractory melts using highly concentrated heat fluxes, are considered. The results of physicochemical studies of the initial silicate materials (basalt, waste oil shale and ash) and the obtained aluminosilicate glasses are presented. Tab. 1, ill. 2, bibliography: 3 titles.
The results of X-ray diffraction studies of preserved zincite samples subjected to dynamic compression (28 GPa) and the Debyegrams of ZnO crystals grown by the hydrothermal method are presented.
Three new modifications of ZnO (I, II, III) have been synthesized. X-ray diffraction pattern of ZnO (I) is indexed in a hexagonal unit cell with a = 4.121 (2) & Aring ;, c = 15.114 (5) & Aring ;, V = 222.3 & Aring; 3 , Z = 12, & rho ; subtraction = 7.293 g / cm 3 , Fedorov group P6 3 / mmc. X-ray data for ZnO (II) are indicated in a rhombic subcell with a = 5.997 (2) & Aring ;, b = 5.267 (1) & Aring ;, c = 2.369 (1) & Aring ;, V = 74.8 & Aring; 3 , Z = 4, & rho; subtract = 7.222 g / cm 3 . The X-ray diffraction pattern of ZnO (III) is indexed in a primitive monoclinic cell with a = 7.931 (8) A, b = 7.911 (4) A, c = 2.995 (1) A,? = 91.07 (4) °, V = 188 & Aring; 3 , Z = 8, & rho; subtract = 5.749 g / cm 3 ... The debyegram of zinc oxide synthesized by the hydrothermal method corresponds to a primitive monoclinic unit cell with a = 6.896 (14) A, b = 6.387 (19) A, c = 5.468 (21) A, ?; = 99.25 (33) °, V = 237.7 & Aring; 3 , Z = 10, & rho; subtract = 5.684 g / cm 3 .
Tab. 3, ill. 2, bibliography. 30 titles
A systematic approach from the standpoint of synergetics to the production of high-quality transparent ceramics is considered. At all stages of the production of transparent ceramics, it is necessary to achieve an optimal reduction in the degree of non-equilibrium of the system: when preparing a powder, including its synthesis, introducing densifying additives and heat treatment, it is necessary to optimally reduce the sintering activity. When obtaining the molding mass, molding and removing the binder, as well as during sintering, the formation of aggregates and local seals with strong solid bridges between particles, which lead to the penetration of pores into crystals, should be excluded. Il. 2, bibliography: 24 titles.
Analytical dependences are obtained for the bulk density of monodisperse powder systems, taking into account the properties of particles. Structural and percolation approaches, as well as taking into account the thickness of the phazon or boundary layers, make it possible to significantly simplify the assessment of the properties of filled powder compositions. It is shown that the calculated and experimental data are in good agreement. Il. 4, bibliography: 8 titles.
The physical and technical characteristics of powders of monofraction electrofused corundum of fraction F240, produced by JSC RUSAL Boksitogorsk (Russia), and F240 Alodur WSK, ZWSK, SWSK, produced by Traibacher Schleifmittel (Austria) have been determined. The influence of the shape of grains of electrofused corundum on open porosity, permeability and ultimate strength of porous permeable ceramics has been studied. A quantitative relationship has been established between the ultimate strength at normal, diametrical compression and bending of porous permeable ceramic samples made of electrocorundum powders. Tab. 4, ill. 2, bibliography: 7 titles.
The technological properties of a number of granite rocks have been investigated, and the effectiveness of their use as fluxes of porcelain masses has been shown. The possibility of obtaining low-temperature porcelain under the conditions of intensified heat treatment has been revealed. The phase composition, microstructure and properties of materials have been studied. The influence of the properties of the liquid phase on the formation of the structure, operational and decorative characteristics of porcelain made using energy-saving technology has been established. Tab. 3, ill. 2, bibliography: 5 titles.
Prospects for the use of reference materials on the best available technologies produced by the sectoral technical working groups of the European Bureau for Integrated Pollution Prevention and Control in the domestic practice of producing ceramic products are considered. The European experience, summarized in reference materials, can be taken into account both in the development of regulatory documents and in the practice of designing and operating enterprises, which will improve the energy efficiency of production and reduce the burden on the environment. Tab. 3, bibliography: 24 titles.
The morphological features of powders of the same chemical composition in the system Al 2 О 3 - ZrO 2 - СеО 2 with different sequence deposition of components. The schemes used for the preparation of precursors of this system make it possible to obtain powders of a given chemical composition with a high degree of completeness of deposition and with individual particle sizes of about 20 nm. In this case, the morphology of the synthesized powders, their agglomeration and porous structure depend on the conditions for obtaining precursors. Tab. 3, ill. 3, bibliography: 8 titles.
The preparation of fine powders of yttrium-aluminum garnet (YAG), a starting material for ceramics, with the use of secondary aluminum butylate and crystalline salt hydrate - yttrium chloride hexahydrate - is considered. It was revealed that, depending on the synthesis conditions and temperature, solid products of various chemical forms are formed. The conditions for the synthesis of the YAG crystalline phase by heat treatment of the resulting precipitates at a temperature of & # 8805; 900 ° C. Il. 2, bibliography: 7 titles.
The processes of phase formation and structure formation in the Al - MgCO 3 - SiO 2 - C system during self-propagating high-temperature synthesis are considered. The dependences of the structure and phase composition of the resulting composite materials on the ratio of the initial components have been determined. The possibility of creating ceramic composite materials based on spinel and silicon carbide phases as a result of using the method of self-propagating high-temperature synthesis is shown. Il. 4, bibliography: 11 titles.
