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Polishing suspensions and powders presented on the world market for polishing a wide range of optical parts used in the manufacture of laser gyroscopes are considered. Their main technical parameters determining the quality of the resulting polished surfaces of optical parts are given. A list of polishing suspensions and powders most suitable for the manufacture of optical parts of laser gyroscopes is proposed.
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Diagnostics of magnetic susceptibility of ferroimpurities (present in the raw components of glass and ceramic products), for the removal of which magnetic separation is widely used, can be carried out using a new magnetic rheological method. Three options for its implementation are described. Results ferroimpurities’ magnetic susceptibility determination, consisting in natural sand and feldspar, are obtained.
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An energy- and resource-saving plasma technology for glazing autoclaved building materials has been developed. It has been established that the introduction of colemanite into the initial charge makes it possible to increase such performance indicators as frost resistance, water resistance and microhardness. The features of the formation of the macro- and microstructure of the glaze coating when treating the front surface with a plasma jet were studied.Key words: glazing, plasma jet, autoclave hardening wall materials, water resistance, frost resistance, microhardness.
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It is shown that the extracted natural quartz sands, widely used in glass, refractory, ceramic, foundry and other industries, as a rule, do not meet the requirements for granulometric composition set by industry standards. Studies have been conducted and an effective method of processing quartz sands has been proposed in order to improve the granulometric composition using a cross-flow pneumatic separator.
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The possibility of using pegmatite dumps in the production of ceramic materials is shown. Microcline pegmatite according to the results of research of dielectric and technological properties in the future can be used in the production of electroceramics. Compositions of ceramic granite tiles on the basis of plagioclase pegmatite, clay, kaolin, quartz with low water absorption 0,43…0,28 % have been developed. On the basis of pegmatite of microcline-plagioclase composition, as well as fine fractional wastes of enrichment of pegmatite, clay, kaolin, finely ground quartz, facing tiles with high bending strength (32 MPa) have been obtained.
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Cubic pyrochlore of the composition Bi2Ni1/2Co1/2Ta2O9 ± ? (sp. gr. Fd-3m, a = 10.5261(8) ?) was synthesized for the first time from the corresponding oxides by the solid-phase reaction method. The complex oxide is characterized by a porous microstructure formed by partially fused elongated crystallites with an average longitudinal size of 1…2 ?m. The chemical state of transition element cations in pyrochlore was characterized by photoelectron spectroscopy (XPS) and NEXAFS.
A characteristic shift of the Ta4f spectrum toward lower energies by 0.8 eV is observed for pyrochlore, due to which the effective charge of tantalum cations is +(5 – ?). The absorption spectrum of pyrochlore in the region of the Co2p absorption edge is a superposition of the spectra of CoO and Co3O4. According to the nature of XPS, NEXAFS Ni2p spectra, nickel ions are in the Ni (II, III) state.
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The paper investigates the process of “soft” mechanochemical synthesis of the CuO/ZnO/Al2O3 composite using copper/zinc hydroxocarbonates and aluminum oxide as feedstock. Using the methods of X-ray phase and synchronous thermal analysis, the patterns occurring at the stage of mechanochemical activation and further heat treatment have been studied. The effect of the mill's energy stress on the textural properties of the composite is shown. By the method of low-temperature adsorption-desorption of nitrogen, it was found that in the process of mechanochemical synthesis, the total specific surface of the samples changes slightly, while the nature of processing has a significant effect on such textural characteristics as pore size distribution, active surface and dispersion of copper. Using the thermoprogrammable reduction method, the temperature ranges of activation of the composite for its use as a catalyst were obtained. The positive effect of mechanical activation on the formation of the composite structure, hich makes it possible to use it as the main component of the catalyst for the production of ammonia, hydrogen and methanol, is shown.
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The physicochemical characteristics of the commercial bentonite S-4205-02 (Bentovin), as well as its structural parameters, are given. Clay agglomerates were mainly up to 10…20 ?m in size. X-ray spectral analysis showed rather high content of Fe2O3, Na2O, CaO, which corresponded to the ferruginous-aluminum variety of montmorillonite with a predominance of Na+ and Ca2+ ions in the interlayer space. The presence of potassium indicates the illite presence. According to the X-ray phase analysis, the main component of the product was montmorillonite (MM) with impurities of quartz/cristobalite, kaolinite, illite, hematite. Thermal analysis curves and the infrared spectrum of bentonite were analyzed. The specific surface area was 58 ± 6 m2/g (BET). On the basis of this bentonite and orthophosphoric acid (OPA), a geopolymer bentonite phosphate binder has been for the first time synthesized. Using X-ray and IR spectral analysis, it was shown that when reacting aluminosilicate powder with OPA, the MM structure was completely destroyed with the formation of aluminum and silicon phosphates.
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The work is devoted to the synthesis of silicon oxycarbide composite modified with titanium oxide by joint mechanical treatment of white soot and activated carbon with TiO2 particles deposited on its surface. The deposition of titanium oxide was confirmed by elemental analysis data. Scanning electron microscopy showed that the size of the particles does not exceed 100 nm. The structure of the obtained materials was studied using such methods as X-ray diffraction and IR spectroscopy. It was found that the silicon oxycarbide composite is highly amorphous; the XRD patterns displayed peaks, which can be attributed to the plane reflections of anatase. The investigation of the IR spectra showed the presence of bands corresponding to vibrations of Ti–O–Ti and Ti–O–C bonds. The porosity of the synthesized samples was studied using nitrogen low-temperature adsorption/desorption. It was revealed that the composite has a fairly developed porous structure with a predominance of meso- and macropores. The material is suggested to be used as a photocatalyst for the destruction of organic compounds in purification processes.
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The morphology of nickel and cobalt oxides deposited on various substrates, namely ?-alumina and silica gel, is investigated. The main purpose of the work was to study the effect of synthesis methods, such as impregnation and mechanochemical synthesis, on the textural characteristics and surface morphology of the resulting composites.
The characteristics of the composites were determined using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy and the method of low-temperature nitrogen adsorption/desorption. The results showed that the choice of the synthesis method significantly affects the size and shape of the oxide particles, as well as the distribution of nickel and cobalt oxides on the substrate surface. The impregnation method ensures a uniform distribution of metal oxide particles, but at the same time, they have a great tendency to agglomeration, especially cobalt oxide.
The mechanochemical method makes it possible to increase the lability of the components and increase the degree of adhesion, which makes it possible to achieve greater dispersion of metal oxides. This is achieved by a controlled degree of encapsulation of the oxides in the substrate. The data obtained can be useful for the development of new composite materials with improved catalytic and structural properties.
