VOL 93, No. 12 (2020)

The conditions for the formation of microregions with polarization-dependent birefringence in sodium-borate glasses with different Na ₂ O contents by a femtosecond laser beam are found. The dependences of the phase shift in the light passing through the birefringent regions on the parameters of the laser exposure and on the chemical composition of the glass have been established. It is shown that an increase in the Na ₂ O content leads to a decrease in the minimum number of pulses required for the formation of regions with polarization-dependent birefringence, as well as to the appearance, under certain conditions, of a special type of modification, for which the slow axis of birefringence parallel to the plane of polarization of the laser beam

The results of a study of the use of non-destructive contactless methods of optical spectroscopy - registration of diffuse reflectance spectra in the UV-VIS-NIR range and photoluminescence for the identification of porcelain products are presented. According to the color characteristics and the list of optically active luminescence centers (OACL), the porcelain products were graded according to the composition and state of the redox medium during firing. It is shown that the chromaticity of porcelain can be controlled by the combination and ratio of the intensities of the centers of color and luminescence. A decrease in the intensity of the OACL Fe ³⁺ band is mainly associated with a change in the coordination of iron Fe ^{3 +} O ₄ & # 8594; Fe ³⁺ O ₆ in bone china

The results of the study of the dielectric constant & # 949; modified sodium silicate compositions (SNK) depending on the content of the modifying zinc-containing aqueous solution (zinc acetate) and the curing time of the compositions. The characteristic changes in the value of & # 949; are revealed. It is shown that for the system under study, the nature of the change in the value of & # 949; corresponds to the nature of the change in the strength and water resistance of the modified samples depending on the content of the modifier in the SNK. Based on the foregoing, the method of dielectric constant for assessing structural changes modified by SNC is characterized as an express method for predicting the properties

The composition of a ceramic pigment using pyroxenite has been developed, including pyroxene minerals - augite, enstatite; in addition, forsterite, serpentine and coloring iron and chromium oxides are present. The compositions of the crystalline phases in pigments depending on the firing temperature have been investigated by XRD and microanalysis. Ceramic pigment with a diopside structure allows to obtain a brown color of the coating when using the pigment in a wide range of firing temperatures of 850 - 1250 ° C, excluding the melting of the pigment, while improving the purity of tone and brightness of the coating

The results of studies of the structure, phase composition, mechanical and chemical properties of aluminosilicate, magnesia-quartz and glass-ceramic proppants (RosProp, BorProp, ForeRCP, Wauli, etc.) are presented. It has been shown that glass-ceramic proppants are superior in performance to ceramic analogs due to the use of a highly efficient method of dispersing a melt jet into droplets for spherization of particles and structural features manifested in the formation of a homogeneous dense material represented by microcrystals of pyroxene composition

The results of experimental studies on the generation of X-ray radiation when operating a kitchen piezoelectric lighter in a vacuum are presented. For the first time, a new method for increasing the intensity of X-ray radiation with the piezoelectric effect in high vacuum conditions through the use of an additional electron emitter was proposed and demonstrated. The maximum energy of X-ray bremsstrahlung reaches 14 keV. This means that electrons are accelerated in vacuum in the field of piezoelectric ceramics to an energy of at least 14 keV

The technology of synthesis of fluoromagnesiumapatite powder and technology of coating formation by plasma spraying on its basis are presented. The recommended mode for the formation of a coating based on fluoromagnesiumapatite powder with an open porosity of more than 40 & # 37;, adhesive strength 15 MPa, hardness 190 HB and hydrophilicity is: arc current 300 A, fineness of titanium powder up to 150 microns, fineness of fluoromagnesiumapatite powder up to 90 microns , plasma-forming gas flow rate 20 l / min, distance of titanium powder spraying up to 150 mm, distance of spraying fluoromagnesiumapatite powder up to 50 mm

Ceramic bricks based on low-melting clay and ferro-dust were obtained from self-decaying slags of low-carbon ferrochrome in the temperature range 950 - 1100 ° C, which have grades from M100 to M175, respectively. The highest grades are in bricks fired at temperatures of 1050 and 1100 & # 176; C, respectively M150 and M175, which can be used as earthquake-resistant. Studies have shown that at a brick firing temperature of 950 ° C, the appearance of hematite, wollastonite, diopside and a liquid phase is noted. An increase in the firing temperature to 1000 & # 176; С contributes to the appearance of anorthite and cristobalite. An increase in the firing temperature to 1050 ° C does not lead to special changes, with the exception of an increase in the content of cristobalite, anorthite and a decrease in the content of feldspar. A further increase in the firing temperature to 1100 ° C leads to an increase in the content of anorthite, diopside and cristobalite. Physicomechanical parameters increase due to the formation of anorthite and diopside in the samples