VOL 91, No. 6 (2018)

The regions in the volume of lanthanum-oborogermanate glass, modified by a femtosecond laser beam, have been investigated by optical microscopy and confocal Raman spectroscopy. The data obtained show that, at the stages preceding the formation of the LaBGeO ₅ microcrystal, germanium nanocrystals are precipitated in the local heating zone when exposed to a femtosecond beam in a certain range of laser pulse energy. The correlation between the conditions of laser irradiation, leading to the appearance of germanium nanocrystals and the conditions with a high probability of ensuring the crystallization of the phases of the low-temperature modification of lanthanum borate and stillwellite-like lanthanum borogermanate, suggest that germanium nanocrystals can serve as nuclei for heterogeneous crystallization of LaBO ₃ and LaBGeO ₅

The sol-gel processes occurring during hydrolysis in the presence of a surfactant, diethylamine, have been studied. It has been shown that the rate of tetrabutoxytitanium hydrolysis at minimum water concentrations and in the presence of diethylamine is determined by the competition between the condensation processes of TiO ₂ nanoparticles and the adsorption of diethylamine molecules on the surface of TiO ₂ particles.

The results of theoretical and experimental studies of methods for obtaining powder fillings with a relative density of more than 0.50 for subsequent sintering of samples of high-density ceramics based on aluminum oxide are presented. To achieve the specified compacting density, we used the method of selecting the fractional composition of the spherical corundum powder, based on the known theoretical models of dense regular and random packings of spheres of different sizes. The prospects of using the described methods in the technology of manufacturing ceramic products are assessed.

The electroflotation extraction of highly dispersed TiO ₂ and Ti (OH) ₄ particles has been studied. It was found that in aqueous solutions of electrolytes at pH = 2... 12 electroflotation of TiO ₂ proceeds ineffectively: the degree of extraction is 10... 15 & # 37;. In the presence of a surfactant, the degree of extraction is 25... 30 & # 37;, in the presence of a surfactant and a coagulant Fe ⁺³? 90... 95 & # 37 ;. Electroflotation of Ti (OH) ⁴ proceeds efficiently: the degree of extraction at pH = 3 reaches 99 & # 37;, the electroflotation time is 5... 10 min, energy consumption is 0.5 kWh / m3 of solution

Within the framework of a dynamic uncoupled problem of thermoelasticity for a half-space, the effect of pulsed laser radiation on glassy and ceramic materials is considered. Analytical relations are obtained, which are the criteria for the thermal strength of materials for three temporal forms of laser pulses of nanosecond duration and make it possible to determine non-destructive annealing modes. The influence of the temporal shape of the laser pulse on the annealing regimes of materials is shown. It was found that the use of laser pulses with a steep front and a protracted falloff leads to a decrease in thermoelastic stresses in the material.

The results of the analysis of research in the field of developing compositions and methods of applying high-temperature coatings for the protection of various metals and alloys are presented. The relevance of further developments of heat-resistant sitall coatings for the protection of nichrome steels and alloys during their operation at high temperatures is shown.

The influence of a modified coating applied to the surface of foam glass on the ability to absorb electromagnetic radiation in the high-frequency range is considered. It was found that the coating obtained on the basis of a liquid glass composition with ilmenite with a particle size of 3 microns improves the radio-absorbing characteristics of the foam glass. When contained in the composition of the coating 1.5 & # 37; ilmenite, the absorption coefficient of foam glass at a frequency of 120 GHz increases by 4 times, at a frequency of 260 GHz - 2 times in comparison with foam glass without coating

On the basis of a patent search and theoretical calculations of physicochemical properties, the compositions of enamels were selected and refined, which were synthesized and investigated for consistency in LTEC with the metal, for resistance to alkaline solutions at elevated temperatures. The best characteristics in terms of resistance to alkaline solutions were shown by the frit of the composition ShchSF-1. The corrosion rate (test temperature for alkali resistance 80 ° C) of the enamel coating was only 0.015 g / (m2 h), which is 20 times lower than the corrosion rate of chemically resistant MK-5 enamel