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Ключевые слова: microstructure

Effect of substrates on the photocatalytic activity of the composite coating fabricated by detonation sprayed Ti powders

https://doi.org/10.58224/2618-7183-2025-8-5-3
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Аннотация
Composite coatings based on titanium oxides were successfully deposited on fine-grained concrete and porcelain tile substrates using a robotic complex for detonation spraying. The study focused on the influence of substrate roughness and composition on the microstructure, phase composition, and photocatalytic properties of the coatings. Dense, uniform coatings with a bimodal lamellar microstructure and thicknesses ranging from 20–30 µm on concrete to 250–300 µm on porcelain tiles were obtained without cracks or significant porosity. It was observed that the phase composition of the coatings, which included a mixture of titanium, anatase, rutile, TiO, and Ti₂O₃ phases, remained unaffected by variations in the substrate composition. Regardless of the substrate material used, all coatings exhibited similar phase constituents. However, the surface roughness of the substrates played a crucial role in determining the microstructure and photocatalytic performance. The rougher concrete surface promoted a higher anatase content, resulting in enhanced photocatalytic activity compared to coatings on smoother porcelain tiles. Coating thickness and porosity did not significantly affect photocatalytic efficiency. Additionally, the kinetic constants of the obtained coatings exceeded those of commercial sol-gel coatings and aligned with values typical for thermally sprayed coatings. The obtained results indicate that composite titanium oxide coatings demonstrate high potential for industrial applications where effective breakdown of organic pollutants on diverse surfaces is required.
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Wall materials based on low-grade loams and industrial waste

https://doi.org/10.58224/2618-7183-2025-8-5-4
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Аннотация
Clay raw materials used in Kyrgyzstan for the ceramic industry characterized as low-plasticity , highly sensitive and saline. In addition, the high content of carbonates in loams leads to the production of low-quality bricks. In order to obtain ceramic bricks with high-quality performance characteristics, it is necessary to use innovative approaches in the preparation of clay raw materials.
The raw used materials were local loess-like loams from the Orok deposit and ash from the Bishkek thermal power plant and a surfactant – sodium naphthenate. The loam and ash subjected to mechanochemical activation by joint grinding in activator-mixer and adding sodium naphthenate together with mixing water. The dried cylindrical samples fired in the temperature range of 900, 950 and 1000 0 C.
The results of the studies showed that mechanochemical activation of ash-clay raw materials increases the plasticity of the clay-ash mass by 140 %, while reducing the molding moisture and sensitivity coefficient.
The sintering process is intensified: at a firing temperature of 950 0C and 60 % ash, it is possible to obtain a shard with a density of 1.57 g/cm3 and water absorption of 17 %. The compressive strength is 16.3 MPa.
Amorphization and destruction of raw material particles contribute to an increase in the glass phase content. As a result, open pores are tightened, forming a strong monolithic structure.
The obtained samples based on mechanochemical activation with the addition of 60 % ash have the M150 grade and frost resistance of F 25.
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Influence of mechanical activation on the characteristics of glass concrete

https://doi.org/10.58224/2618-7183-2025-8-4-4
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Аннотация
This work presents the study of effect of mechanical activation on the properties of glass concrete binder, based on mechanically activated glass and calcium oxide. The goal of the study was to identify patterns of changes in the microstructure and phase composition of the material with different durations of grinding and subsequent hydration.
We found that under mechanical activation for 12 minutes, all calcium oxide enters into a chemical reaction with the formation of the mineral combeyite (Na₂Ca₂Si₃O₉). Further hydration of the material leads to the transformation of combeyite into diverite (Na₂Ca₃Si₆O₁₆) and wollastonite (CaSiO₃). The microstructure is characterized by lamellar structures, an increase in strength is provided by a decrease in the particle size and an increase in the chemical interaction of the components.
It is shown that the duration of mechanical activation has a significant effect on the physical and mechanical characteristics of the material. A correlation was established between the duration of grinding and the strength and elastic modulus indices. Thermal and moisture treatment additionally increases the strength of the material, reaching values over 100 MPa.
The obtained results demonstrate the potential of the proposed technology for creating highly efficient building materials with specified physical and technical characteristics, contributing to the savings of traditional cement binders and reducing the pollution of the construction industry.
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Functionalization of one-component cement silicate paint

https://doi.org/10.58224/2618-7183-2024-7-5-5
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Аннотация
The paper presents the results of a study devoted to expanding the functional properties of one-component cement-silicate paints based on white Portland cement, soluble sodium glass and a hardening retarder (sodium phosphate). Existing compositions, despite their exceptional performance qualities, are not able to provide the entire range of required functional characteristics. Therefore, in order to expand the areas of cement silicate paints application, additives based on aluminum powder and nano-sized titanium dioxide were introduced into the coating composition. This resulted in the increase in the electrical conductivity of the coating and made the paint self-cleaning due to photocatalysis.
The study showed that the introduction of nano-sized titanium dioxide particles into the paint composition provides the rapid degradation of organic pigments (within 2 days) due to the photocatalysis reaction occurring under the influence of ultraviolet solar radiation. The pigments are further removed due to precipitation. This helps to maintain the aesthetic properties of the paint even in high dust conditions, for example, in conditions of sandstorms, which are frequent in the African climate.
The introduction of aluminum powder into the paint composition reduces its electrical resistance (in a wet state) from 5.05 kOhm for the reference sample to 2.7 kOhm for the modified sample. The thickness of the applied paint was 350 microns. This can help the coating to absorb man-made electromagnetic radiation due to shielding, while preventing the accumulation of static electricity on the surface, which also contributes to less dust in the premises. In addition, the use of aluminum powder instead of traditional electrically conductive carbon-containing additives allows maintaining the aesthetically pleasant white color of the paint.
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