The purpose of this work was to study the wear resistance of samples obtained by selective fusion of electroerosive titanium powders produced by processing Titanium metal alloys of the VT20 brand.

Methods. The following equipment was used during the research: a plant for producing electroerosive Titanium powders original patented; raw materials for producing Titanium powders VT20 alloy; working fluid isopropyl alcohol; a plant for selective alloying original patented; equipment for studying the wear resistance parameters of an additive sample automated friction machine Tribometer, CSM Instruments. The material of the counterbody is Stainless Steel AISI 420.

Results. As part of the task aimed at studying the wear resistance of samples obtained by selective fusion of electroerosive Titanium powders produced by processing metal waste, the following was established: the coefficient of friction of the surface of the sample under study ranges from 0.126 to 0.435; the amount of volumetric wear is 4.972 mm3x10-5. Experimentally, a jump in the coefficient of friction was established at the initial moment of tribological testing of the sample, which is associated with relatively high roughness and wear characterized by smoothing of the hard surfaces of the sample. It has been experimentally established that in a contacting pair a Titanium sample and a counterbody both touching surfaces wear out almost uniformly. At the same time, the width of the wear plate of the test sample ranged from 1.23 to 1.28 mm. The relatively high wear resistance of the studied sample, obtained by selective fusion of electroerosion titanium powders, was facilitated by a porous defect-free structure and a relatively small grain size.

Conclusion. The data obtained will make it possible to select the most rational area of practical application of the new additive material.

The purpose is to study the tribological characteristics, wear resistance and adhesive strength of a Tungstencontaining coating obtained by electric spark alloying with VK6 alloy on a steel substrate made of 50XGA steel, as well as to establish the relationship between structural and phase features, microhardness and the behavior of the material under conditions of contact friction.

Methods. The objects of the study were sample 1, an uncoated steel substrate made of 50XGA steel, and sample 2, a steel substrate made of a similar material with a Tungsten-containing reinforcing coating applied by electric spark alloying with an electrode material based on a hard alloy VK6. The microstructure of the surface and cross-sections was studied on a WIN SEM A8000. The elemental composition was determined by energy dispersive X-ray spectral microanalysis. The phase composition was studied by X-ray diffraction. The microhardness was determined using the automated AFFRI DM-8 system. Tribological tests were performed on Tribometer GSM Instruments, the adhesive strength of the coating was evaluated on a Revetest device.

Results. The formation of a multiphase composite structure on the surface of the steel substrate, including the phases γ-Fe, W and α-Fe, has been revealed. It was found that the application of a strengthening coating significantly increases the microhardness of the surface: for a coated sample, this indicator was 13.25 GPa, while the microhardness of the uncoated substrate was 3.01 GPa. According to the results of tribological tests according to the "ball-disc" scheme, a decrease in the wear factor from 374.8 to 80.76 мм³·Н ⁻ ¹·м ⁻ ¹ was found. Scratch testing showed that the critical load of coating failure was 117.52 N.

Conclusion . The data obtained make it possible to substantiate the prospects of practical application of a Tungstencontaining coating formed by electric spark alloying with a VK6 electrode to increase the wear resistance of mechanical engineering parts operating under conditions of friction and intense contact wear.

The purpose of this work was to study the microhardness of samples obtained by selective fusion of electroerosive iron-chromium-nickel powders produced by processing metal waste.

Methods. When carrying out research aimed at achieving this goal, the following equipment was used in accordance with the experimental plan: an installation for the production of electroerosive Iron-Chromium-Nickel powders original patented; raw materials for the production of Iron-Chromium-Nickel powders alloy grade 20X25H20X2; working fluid isopropyl alcohol; installation for selective fusion original patented; The equipment for studying the microstructure of an additive sample is the Nova NanoSEM 450 electronic scanning microscope, which provides high spatial resolution

and the possibility of detailed analysis of structural elements of the material; the equipment for studying the microhardness of an additive sample is the Instron 402 MVD micrometer (Great Britain). The tests were carried out with an indenter load of 100 g on ten prints with a free choice of injection site in accordance with GOST 9450-76. The loading time of the indenter was 15 s. Before the microstructural analysis of the additive sample was carried out, the metallographic section was prepared.

Results. Based on the conducted studies aimed at studying the microhardness of samples obtained by selective alloying of electroerosive Iron-Chromium-Nickel powders produced by processing metal waste, it was found that the additive sample has a practically nonporous microcrystalline structure; the average microhardness is about 6.4 GPa. These microhardness values are achieved by an almost porous microcrystalline structure and the presence of highly solid phase components.

Conclusion. The research carried out will make it possible to select the most rational area of its practical application for a new alloy obtained by selective fusion of electroerozionic Ferro-Chromium-Nickel powders

The purpose is to study was to anodize D16T Aluminum alloy using various methods and then measure the thickness and microhardness of the resulting layer.

Methods. To achieve this goal, known Aluminum anodizing methods were studied and tested, and a combined method was proposed: anodizing in aqueous electrolyte solutions; anodizing in molten salts; plasma-electrolytic anodizing; plasma-electrolytic anodizing in molten salts. Four anodizing setups were constructed. A series of experiments were conducted. The resulting samples were tested for microhardness and coating thickness.

A simple ring-shaped part was chosen for the study. This shape allows for understanding oxide growth on both the outer and inner surfaces of the sample. When selecting an alloy for the experimental studies, various Aluminum alloys were considered:

Alloys with the lowest amount of alloying elements, such as pure Aluminum, are easiest to anodize but are not used in practice.

Alloys with low alloying element content or alloyed with Magnesium (AMg3, AMg6) have lower microhardness and strength than duralumin alloys (D16T), which also limits their application in some industrial applications. D16T alloy was chosen as the test material, as it is one of the most common and difficult alloys for high-quality thicklayer hard anodizing.

Results. Four anodizing methods were investigated during the study. A proprietary anodizing method was developed: plasma electrolysis in molten salts. This method is distinguished by its electrically conductive environment and its higher chemical activity during the anodizing process. Compared to samples obtained by known methods, this anodizing method demonstrated higher microhardness of the resulting coating, approximately 1704 HV0.2.

Conclusion. The experiments carried out, reflecting the dependence of the microhardness of the resulting layer using each anodizing method, showed that anodizing in aqueous electrolyte solutions has a microhardness 2 times greater than the microhardness of the D16T alloy, plasma-electrolytic anodizing made it possible to increase the microhardness by 4 times, and the developed method of plasma-electrolytic anodizing in molten salts made it possible to increase the microhardness by 9 times.

Purpose . Study of the fatigue crack growth kinetics during cyclic bending of the sintered diffusion-alloyed Fe-Ni-CuMo material (PL-N2D2M grade) and establishment of quantitative patterns of the influence of residual porosity (1020%) and the time of isothermal exposure during sintering (30-90 minutes) on the fatigue durability. 

Methods. The samples were made by static cold pressing followed by sintering at 950[0] C in the medium of dissociated ammonia. Cyclic bending tests were carried out on a vibration stand with a frequency of 7 Hz with an amplitude of 3.5 mm in the loading cycle. The crack growth kinetics were recorded by the method of electro-potentials with signal amplification by an analog-digital converter and recording in the LGraph2 program. The potential difference was converted to crack length using calibration curves, and S-shaped curves were plotted in the "crack length-number of cycles" coordinates.

Results. A three-stage S-shaped fatigue failure pattern was established for all the samples studied. Reducing the porosity from 20% to 10% leads to an increase in the number of cycles before failure, an extension of the initial crack initiation stage, and a decrease in the rate of crack growth in the linear stage. Increasing the sintering time from 30 minutes to 90 minutes has a positive effect on fatigue strength, with the maximum effect observed at a porosity of 10% and a slight effect at 20%.

Conclusion. Porosity is a determining factor in fatigue durability, whereas sintering time is effective only for low-porous materials. The electropotential method has confirmed its applicability for continuous monitoring of crack growth kinetics in real time. The obtained patterns allow for the reasonable selection of technological modes for the production of parts from powder materials that operate under cyclic loads (gears, levers, eccentrics, transmission elements).

Purpose. To study the adsorption mechanisms of Li, Na, and K atoms on Boron-Carbon nanolayers (BC, BC₃ , and BC₅ ) with periodic substitution of Carbon by Boron, and to evaluate the effect of Boron concentration on the energetic and electronic characteristics governing the sensor response.

Methods. The calculations were performed within density functional theory using the hybrid B3LYP functional and the 6-31G basis set for cluster models of the nanolayers. Dangling bonds at the cluster edges were passivated with hydrogen atoms to minimize edge effects. Adsorption was modeled by stepwise approach of alkali metal atoms toward three key surface sites (hexagon center, above a C atom, and above a B atom) with a step of 0.2 Å from 3.2 Å down to the equilibrium separations. Energy profiles were constructed from the computed potential energies, and the equilibrium distances and interaction energies were determined.

Results. Stable adsorption complexes were obtained for all systems: the equilibrium configurations exhibit negative interaction energies, and the hexagon center is the energetically preferred adsorption site. The interaction energy attains the largest magnitudes for the BC ₅ nanolayer (up to −3.04 eV for Li, −2.44 eV for Na, and −2.71 eV for K). The charge transfer has a pronounced donor character: the metal atoms acquire a positive charge (+0.40 to +0.86 e), whereas surface boron atoms can accumulate negative charge (down to −0.86 e). The density-of-states spectra show the emergence of additional states near the conduction band minimum and a shift of the Fermi level. The widest band gap is characteristic of BC ₃ (1.25–1.40 eV).

Conclusion. All Boron-Carbon nanolayers exhibit energetically favorable adsorption of alkali metals. Varying the boron concentration makes it possible to tune the interaction energy and electronic characteristics, which is important for sensing and sorption applications.

Purpose – to characterize BN nanofilms from an h-BN target formed by reactive high-frequency magnetron sputtering in an Ar + N2 mixture on various substrates.

Methods. Reactive high-frequency magnetron sputtering of boron nitride onto silicon, sapphire, glass-ceramic, polycor, and polyamide fabric substrates was performed using varying sputtering parameters (power 50–80 W, time 1800–2700 s, and solid-state substrate temperature ~ 430 K). Magnetron nanofilms were studied using atomic force microscopy, scanning and transmission electron microscopy (including high-resolution mode), energy-dispersive X-ray microanalysis, X-ray diffraction, Raman scattering, Fourier transform infrared spectroscopy, and optical absorption spectrophotometry. Modeling of the optical characteristics was performed using density functional theory in the randomized phase approximation.

Results. The nanostructuring features were precisely studied and the characteristic dimensions of the nanostructures in the formed boron nitride MNPs were measured using. The EDA data confirmed the stoichiometry of the elemental composition of the MNPs on all substrates, and the linearity of the thickness increase depending on the magnetron sputtering time was established based on the color of the reflected light. Raman and x-ray diffraction data showed that polycrystalline MNPs with inclusions of hexagonal h-BN and cubic c-BN and free boron are formed during the RF MR of BN. The crystallinity of h-BN in the MNPs increases with increasing substrate temperature starting from Tп ~ 600 K. Model calculations of the optical characteristics are consistent with spectrophotometric measurements of the absorption coefficient and confirm the polymorphizm in the MNPs.

Conclusion. A comprehensive characterization of boron nitride nanoparticles from an h-BN target of a silicon, sapphire, glass-ceramic, polycor, and polyamide fabric substrates formed by the RF magnetron sputtering method revealed that the sputtering temperature and time have the most significant impact on their nanostructuring and phase composition.

Purpose – to experimentally and theoretically evaluate the dynamics of adsorption of vapors of three organic solvents (acetone, isopropanol, toluene) on activated carbon of class A1 filters, to identify the relationship between the physicochemical properties of the adsorbates and the protective action parameters, and to determine the efficiency of thermal regeneration of the adsorbent.

Methods. Adsorption experiments were carried out on an original fixed-bed setup at an air flow rate of 0.02 L/s, temperature of 24.5°C, and relative humidity of 35%. For each adsorbate, the breakthrough time, mass of adsorbed substance, and volume of purified air were measured. The degree of recovery of adsorption capacity after thermal regeneration (110°C, 1 h) was evaluated. Adsorption isotherms were simulated using the Grand Canonical Monte Carlo method, and isosteric heats of adsorption were calculated.

Results. No direct correlation was found between the mass of adsorbed substance and the breakthrough time. Acetone exhibits the maximum adsorption capacity (0.22 g) but the shortest breakthrough time (240 s) due to its high volatility. Isopropanol provides the longest breakthrough time (780 s) with a lower adsorbed mass (0.18 g) due to the formation of hydrogen bonds. Toluene occupies an intermediate position (363 s, 0.14 g) because of steric constraints. The degree of recovery after regeneration was 82–85%, indicating the presence of an irreversibly bound fraction (15–18%). The simulation confirmed the key role of electrostatic and hydrogen-bonding interactions, as well as the energetic heterogeneity of the carbon framework surface.

Conclusion. The obtained data are important for predicting the service life of carbon filters, selecting the appropriate adsorbent for specific volatile organic compounds, and optimizing thermal regeneration regimes based on the polarity and volatility of the adsorbate.

Purpose – сomprehensive characterization of composite materials with Bi₂O₃ intended for radiation protection of biological objects and electronic equipment components from gamma radiation in the energy range up to 662 keV.

Methods. Experimental cylindrical composite material samples were made from epoxy-diane resin ED-20 with PEPA hardener, supplemented with either Bi₂O₃ powder or a mixture of Bi₂O₃ and ZnO in equal molar ratios. They were characterized using atomic force microscopy and scanning electron microscopy, as well as energy-dispersive analysis and phase analysis. The attenuation of gamma radiation from a laboratory source ¹³⁷Cs with a power of up to 10 μSv/h was compared with the count rate intensity of gas-discharge Geiger-Müller counter modules SBM20-1, both encased in a composite material and without it.

Results. Using nano instruments and structural analysis, the particle size distribution of the fillers and their distribution within the epoxy matrix were determined, as well as the structure of bismuth and zinc oxide nanoparticles. Using a gamma ray source, the linear and mass attenuation coefficients of the composite material, as well as the half-value layer of the resulting coatings, were determined.

Conclusion. In a composite absorber based on either Bi₂O₃ powder or a mixture of Bi₂O₃ and ZnO, two interaction mechanisms are involved in the specified gamma-ray range: the photoelectric effect and Compton scattering. Using the XCOM: Photon Cross Sections Database web database, the spectral ranges of the primary attenuation mechanisms were estimated for all composite materials, taking into account their chemical formula and mass content. Absorption due to the photoelectric effect predominates for composite materials up to 400 keV. The maximum emission from the ¹³⁷Cs source occurs at a photon energy of 662 keV, at which the mass coefficients of the samples with these powders are approximately equal to within 10%, due to the Compton effect.

Purpose – generalization of modern methods for the production of nanocomposite materials based on polyvinyl alcohol and polyvinylpyrrolidone, as well as a theoretical study of the mechanisms of interaction of these polymers with single-layer and double-layer Carbon nanotubes to create a new generation of composite systems with improved properties.

Methods. The analysis and systematization of scientific literature data on nanocomposite production technologies has been carried out; original quantum chemical calculations within the framework of density functional theory performed by the author to study the electronic structure and interaction mechanisms of composite components (PVS, PVP, carbon nanotubes).

Results. A review of scientific papers confirmed that the addition of ultra-small amounts of CNTs to the polymer matrix makes it possible to radically change the properties of polymers without significantly increasing the cost of the final material; computational experiments using DFT have made it possible to identify the mechanisms of interaction of polyvinyl alcohol and polyvinylpyrrolidone with Carbon nanotubes, to establish the nature of sorption (physical or chemical), energy binding parameters and the degree of redistribution of electron density in complexes, to create a new composite polymer system; Multiscale modeling is recognized as a key factor in technological progress in organic electronics, allowing to minimize development costs and predict the stability of materials.

Conclusion. The conducted research has led to the formation of holistic scientific ideas about nanocomposite production technologies, and the combination of experimental research and quantum chemical modeling opens up prospects for the development of science and technology, from basic chemical concepts to practical developments in the field of conductive polymers and organic electronics.

Purpose of research. To evaluate the efficiency of Zinc (II) ion removal from aqueous solutions using granulated defecate under dynamic conditions and to select the optimal binder for granulation, providing maximum sorption capacity and mechanical strength.

Methods. Defecate – a sugar production waste containing 60-85 % CaCO₃, organic matter, nitrogen, phosphorus and potassium – was granulated with binders: starch, polyvinyl alcohol, polyvinyl acetate, sodium silicate glue, and crystalline sodium metasilicate. Granules were obtained using a screw granulator followed by drying at 100°C. Model ZnSO₄ solutions with a concentration of 2.1 g/dm³ were passed through a column packed with the granulated sorbent (18.8 g). The total dynamic exchange capacity was calculated as the amount of Zinc ions sorbed until complete saturation. The toxicity of treated water was assessed by white mustard; seed germination; the germination inhibition coefficient was determined.

Results. The highest DEC values (23.4 mg/g) were achieved for granules with PVA and PVAc, which is attributed to the formation of a porous polymer matrix that does not block active sorption centers. Granules with starch and sodium silicate glue showed DEC of 20.0-20.1 mg/g, which is slightly lower due to partial pore blocking or reduced mechanical stability. The optimal binder amount is 5 g per 50 g of defecate: at lower content the granules are fragile, while at higher content costs increase without a significant improvement in sorption capacity. All treated water samples were non-toxic, confirming the safety of the developed sorbents for aquatic ecosystems.

Conclusion. Granulation of defecate with polymeric binders (PVA, PVAc) enables the production of an efficient and safe sorbent for Zinc (II) ion removal from water in dynamic mode. The recommended binder is PVA, providing high DEC, mechanical strength and minimal pore blocking. The proposed technology enables simultaneous utilization of large-scale industrial waste and solving environmental tasks of wastewater treatment from heavy metals, making it promising for industrial applications.

Purpose to assess the content of biologically active components in extracts obtained from wild hawthorn, barberry, and rosehip fruits growing in the Kursk region using the method of maceration and continuous extraction at the boiling point of the solvent in a Soxhlet apparatus, and to compare the obtained values with those obtained by extracting biologically active substances from a mixture of dried fruits in order to identify a synergistic effect.

Methods: extraction of organic compounds; qualitative and quantitative determination of biologically active compounds; UV spectrophotometry; kinetic method for determining the rate constant; methods for determining "oxidative spoilage".

Results. The paper considers known options for using extracts of fruits of garden and wild plants natural sources of antioxidants in the production of functional beverages. Extracts from hawthorn, barberry and rosehip fruits were obtained by maceration and continuous extraction, followed by a comparative assessment of their vitamin content, the amount of flavonoids and the amount of saponins. The option of extracting BAS from a mixture of dried fruits in a Soxlet apparatus with a different mass ratio is considered with an estimate of the amount of BAS extracted, and a combination with a pronounced synergistic effect is identified. The oil extracts are resistant to oxidative spoilage..

Conclusion. It has been established that the differences in the extraction method by different methods are already manifested at the stage of assessing the appearance of the obtained extracts, and extraction in the Soxhlet apparatus is more effective for extracting these groups of compounds. Maceration for the specified time and three cycles of continuous extraction are insufficient for complete extraction under the selected conditions. The transition to combinations of two fruits revealed a synergistic effect in most cases for the extraction of bioactive substances, with the greatest effect observed for the extraction of component C. When switching to three-component mixtures, a decrease in the synergistic effect was observed, and the extraction rate increased under these conditions, reaching the maximum concentration of extractable substances.