VOL 93, No. 1 (2020)

The results of a study of the processes underlying the formation of hollow alumina-magnesia microspheres during chemical dispersion of aluminum-magnesium alloys with an increased magnesium content are presented. The mechanism of formation of microspheres and the factors that determine their structural features and sizes have been clarified. The effect of magnesium additions on the processes of formation of the structure of hollow microspheres and their amount is shown. Studied the fine structure of powders before and after heat treatment

The behavior of mixtures 6Al ₂ Si ₂ O ₇: 12NaOH and 6Al ₂ Si ₂ O ₇: 12NaOH: 2Al ₂ O ₃ during heat treatment. It was shown that after ultrasonic treatment of the suspension, its evaporation, granulation of the paste, and drying, a hydrated LTA zeolite is formed. It was found that at temperatures up to 700 & # 176; C, sodium aluminosilicate Na ₆ Al ₄ Si ₄ O _{17. After heat treatment at temperatures above 800 & # 176; C, sodium aluminosilicate Na 8 Al 4 Si 4 O 18 < / sub>, mullite and nepheline. It is shown that calculations by the isoconversion methods of Friedman (differential) and Kissinger - Akahir - Sunose (integral), for which the temperature range 500 - 800 ° C is of interest, give close values ??of E. An increase in the apparent activation energy with an increase in the degree of conversion indicates changing the reaction mechanism}

On the basis of the natural zeolite of Nakhchivan, zeolite faujasite was synthesized and its physicochemical properties were studied. The zeolite tuffs of the Nakhchivan Kukuchay deposit were used as a natural sample. It was found that the region of existence of faujasite is wide, and the optimal conditions for its hydrothermal synthesis were temperatures of 100 - 200 & # 176; C, the concentration of the thermal solution 10 - 15 & # 37; Ca (OH) ₂, treatment time 50 h

Modification of polyurea with glass microspheres has been carried out. Polyurea compositions of coatings based on them have been obtained. Their properties are assessed. The results of studying the compositions of coatings based on polyurea containing hollow glass microspheres are presented. It is proposed to use such coatings as waterproofing for pre-insulated heat supply pipes. The composition of a coating based on polyurea, containing hollow glass or aluminosilicate microspheres with a diameter of 200 - 300 ?m, functional additives selected from the series, including ammonium polyphosphate, wollastonite, microcalcite with a ratio of glass and aluminosilicate microspheres of 1: 1, was investigated.

A method is proposed for assessing the effect of the size and shape of alumina powder particles on the average radius of the capillaries of the porous structure of alumina ceramics by the geometric coefficient of the shape of particles and their specific surface area. The technique is based on a three-dimensional model of the porous structure of materials, taking into account the geometry of the capillaries. The resulting expression for the mean radius of capillaries is much more accurate than the Kozeny formula and methods based on the model with non-intersecting capillaries, which give underestimated values ??of the radius. It is noted that the effect of the thickness of porous ceramic samples on the gas permeability coefficient is insignificant.

The wetting and spreading of 0.2 N HCl solution over the surface of lead-silicate glasses С87-2 and С78-4 before and after their thermohydrogen reduction was investigated. It is shown that thermohydrogen reduction improves the interaction of acidic solutions with glasses. The results obtained are explained by the appearance of lead on the surface of the studied glasses and their dehydration, which occurs in the process of thermohydrogen reduction of lead silicate glasses.

According to the results of statistical analysis of data on the preparation of slip from quartz glass and data on the scrap of ceramic products, the effect of pH and the duration of rotary mixing of the slip on the probability of occurrence of scrap along cracks was found. The use of data on the zeta potential of slip particles and consideration of the scheme of physicochemical transformations of submicroparticles of quartz glass and silica ash in the slip made it possible to identify the intervals of optimal pH values ??and the duration of rotational stirring of the slip

Elemental chemical composition showed an increased mass content of calcium (Ca = 5.9 & # 37;) in the samples, which contributes to the formation of anorthite, which increases the strength of products, and an increased mass content of carbon (C = 14.79 & # 37;) indicates the introduction of fuel into the raw. The increased mass content of fuel in the raw material promotes uniform sintering inside the ceramic sample. Increased mass content in the sample of iron (Fe = 2.98 & # 37;) and alkali (R ₂ O = Na ₂ O + K _{2 O = 2.57 & # 37;) will promote the formation of a liquid phase at 950 & # 176; C. X-ray phase analysis is confirmed by element-by-element analysis that increased calcium content contributes to the formation of anorthite}