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Based on the concept of cybotaxic groups, a model of nucleation in metasilicate melts has been developed, which takes into account the thermodynamic and kinetic factors of phase transformation. The number of forming nuclei depends not only on the degree of supercooling of the melt, but also on the temperature of its pouring into the mold, during which the kinetic factor is realized.
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A new technology for the formation of a multilayer mineral wool carpet by means of a pendulum zigzag layout of a primary mineral wool carpet is described, which consists in the formation of a loop with a variable height in the primary mineral wool carpet to ensure equality of the feed rate of the primary mineral wool carpet to the pendulum spreader and the peripheral speed of the pendulum at the point where the primary mineral wool carpet leaves it at the point of exit of the primary mineral wool carpet to the pendulum spreader. throughout the zigzag pattern of the primary carpet. Analytical dependencies are given for calculating the parameters of technology that implements a new method of pendulum zigzag layout of mineral wool carpet
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Hits: 6353
The thermal stability of the glass coating of a pipe in the oil and chemical industry has been investigated. It was found that an increase in the thickness of the glass coating leads to a sharp deterioration in the heat resistance of the pipe coating. This phenomenon is associated with an increase in temperature gradients when heating or cooling thick coatings compared to thin pipe coatings. It was found that the high thermal resistance of the glass coating of the pipe mainly depends on the thickness, grade and geometric dimensions of the coating and steel pipe.
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Hits: 6320
The influence of the presence of water-soluble low molecular weight oligomers in a paint composition on the possibility of a single high-temperature firing and decorative properties of coatings, taking into account the type of ceramic surface (porcelain or faience), the composition of pigments and the corresponding mineral fillers, has been studied. A difference was found in the color and tone of coatings, the gloss of the glaze for surfaces of various aluminosilicate modules and temperature regimes.
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Hits: 6764
The results of successful application of the method of laser drilling of micro-holes with a diameter of 30 - 200 µm in glasses with a thickness of 0.1 to 0.8 mm are presented. Achievement of high quality of holes with high productivity of the process is ensured by the use of immersion coolant in the process of piercing holes, which is in contact with the lower surface of the glass.
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Hits: 6696
In the Li
2 O-ZnO-TiO
2 system, a material has been developed for the technology of low-temperature co-firing of ceramics with a view to its use in the production of electronic components. The sintering temperature of the material was reduced from 1075 to 950 & # 176; C due to the introduction of 3.0 & # 37; sintering additive of eutectic composition in the system Li
2 OB
2 O
3 -SiO
2 . The developed ceramics, obtained at 950 & # 176; C, is characterized by a density of 4.14 g / cm
3 , as well as the following dielectric properties:
dielectric constant & # 949; = 23.1 and the dielectric figure of merit Q * f = 832 MHz
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The issue of the prospects of using ceramic composite materials in heat-loaded units of advanced aviation technology instead of metallic materials is considered. Research has been carried out on the manufacture of ceramic composite materials based on silicon carbide, reinforced with whiskers (whiskers), by hot pressing and spark plasma sintering with the use of oxide and nitride sintering additives. A complex of physical, mechanical and thermal properties of composites was investigated.
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Hits: 6669
The effect of molarity (from 3.64 to 1.74 M) of a solution of an alkaline activator (ALA) and temperature (from 10 to 20 ° C) of a mixture of alkali-activated materials (ALA) based on chamotte and metakaolin on the rheological properties was investigated. the development of the structure during curing and the strength of the samples after firing at temperatures of 800 and 1000 ° C. It has been established that a decrease in the molarity of the ALCA and an increase in temperature reduce the viscosity of the AHAM mixture. An increase in the molarity of the PCA and the temperature of the mixture accelerates the process of structure formation and leads to an increase in the strength of the samples during curing from 8.8 to 22 MPa and from 6.8 to 20 MPa after firing at a temperature of 1000 ° C. Also, the density of samples after firing increases from 1270 to 1510 kg / m
3 , and water absorption decreases from 15.4 to 13.4 & # 37;
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Hits: 6632
The development of effective ceramic lining materials is an important industry challenge. Alumophosphate binder materials may be considered new for hydrocyclone applications. This work is devoted to the study of the content of the binder, its modification and calcination temperature on the properties of the final products. Particular attention is paid to the study of the main properties for the use of ceramic materials as lining: porosity, water adsorption, density. Several composite materials were obtained with improved properties due to reinforcement with coarse-grained silicon carbide
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Hits: 6584
An algorithm for calculating the parameters of the structure of silicon carbide ceramic compositions of the system abrasive grain - bond - pores is described. The mathematical formulas required to use the algorithm are given. An example of the implementation of the algorithm in a production environment is given.
