Purpose. Production and research of nickel powders by grinding metal waste of nickel grade PNK-0T1 in kerosene.

Methods. Nickel powder from PNK-0T1 nickel metal waste in aviation kerosene of the TS-1 brand was obtained with the following electrical parameters of the installation: capacitance of capacitors 44.0-45.5 pF; electrode voltage from 115-120 V; pulse repetition frequency 60-65 Hz. The resulting nickel powder was examined by various methods. Microanalysis of powder particles was carried out using a scanning electron microscope QUANTA 600 FEG. The analysis of the size distribution of powder particles was obtained using the particle size analyzer Analysette 22 NanoTec. The X-ray spectral microanalysis of the powder particles was carried out using an energy dispersive X-ray analyzer from the EDAX company, integrated into a scanning electron microscope QUANTA 600 FEG.

Results. Based on the conducted experimental studies, a new method for producing nickel powder has been devel-oped, characterized in that the powder is obtained by electroerosive dispersion of nickel metal residues of the PNK- 0T1 brand in aviation kerosene of the TS-1 brand with a capacitance of 44.5 UF capacitors, an electrode voltage of 120 V and a pulse frequency of 65 Hz, which provides, at low energy costs, the production of new nickel powder materials suitable for industrial use. It has been experimentally established that the shape of the particles of the ob-tained nickel powders is mainly spherical and elliptical. Carbon is present on the surface of nickel particles. The phases of α-modification nickel and β-modification nickel are marked in the phase composition of the particles.

Conclusion. The conducted research will make it possible to select the most rational field of practical application of the electroerosive nickel powder.

The purpose of the work was to study the influence of laser microstructuring modes on the formation of qualitative indicators (the length of the laser exposure zone, microhardness) of the surface layer of parts made of hot-rolled sheet steel grade 30KhGSA.

Methods. The structural medium-alloy steel of the 30KhGSA grade in the hot-rolled state (sheet 6 mm thick) was chosen as the object of research. Special samples were produced by laser cutting to study changes in the structure, structure and microhardness of the laser exposure zone. After laser cutting, one of the sides of the sample was subjected to mechanical milling in order to remove a layer with a modified structure of the material obtained during laser cutting. Next, laser microstructuring of the sample surfaces was performed using a continuous fiber laser. Metallographic and durometric studies were carried out to study the effect of laser microstructuring on changes in the structure and quality of the surface layer.

Results. The peculiarities of changing the microstructure of the laser exposure zone depending on the type of laser treatment are considered. It is shown that, regardless of the type of laser treatment, a "white layer" is formed on the heat-strengthened surface, the thickness of which depends on the parameters of laser radiation: power, speed, spot diameter, focal length. It has been revealed that when milling operations are used as a preliminary mechanical treatment of the cutting edge surface, in the vast majority of cases a white layer is not formed.

Conclusion. The results obtained can be used to create resource-saving material processing processes using highly concentrated energy flows.

The purpose of the study of this article is to identify the effect of laser treatment modes on the color of the steel 04X18H10.

The research methods were reduced to determining ranges for each of the parameters with an example of the desired color. The influence of laser radiation parameters: the power and frequency of laser radiation, the speed of the laser beam, the resolution of the fill of the marked object - contributes to obtaining a certain shade of the color palette according to the RAL standard.

The result of the study was the data obtained, according to which it is safe to say that the speed of movement of the laser beam has a direct effect on the resulting semitone color. At high values of this parameter, the colors become closer to dark halftones, whereas a decrease in speed leads to the opposite effect, it is possible that at low speeds of the laser beam, a slower heating of the object occurs, which leads to light halftones, and with a gradual increase in speed and, accordingly, a possible increase in surface heating temperature, colors begin to form a dark tone. The results obtained by changing the fill resolution parameter make it clear that an increase in this indicator directly affects the saturation of the resulting color with its increase, whereas a decrease in the number of fill lines causes a drop in the color saturation of the marked object.

Conclusion. In this paper, the influence of the factors responsible for obtaining various shades of colors during laser marking of metal is considered, a basic palette of colors is obtained for its subsequent expansion and use for artistic purposes.

The purpose of the study. Development of a technological process for strengthening the body of a road milling cutter by applying an electric spark coating based on VK8 alloy.

Methods. Modern techniques and equipment were used to achieve the set goal. The coatings were applied to pre-prepared samples made from the cutter of the KZTS A6/20 road milling machine using the UR-121 electric spark alloying unit.

Technological parameters: anode - cutter tip (VK8 hard alloy); cathode - cutter body (structural alloy steel); sparking voltage 70 V; operating temperature 18-20°C; NORMA process mode 100 Hz; vibration amplitude of the vibrator VIBRATION 11; electric processing mode MODE 3.

To study the elemental composition and microstructure of the hardening coating, images were taken using an EDAX energy-dispersive X-ray analyzer built into a Quanta 600 FEG scanning electron microscope.

Vickers microhardness testing of samples before and after hardening was performed using an AFFRI DM-8 microhardness tester.

A Revetest scratch tester was used to test strength, scratch resistance, and determine the mechanism of sample failure.

Results. As a result of the experiment, electrospark hardening coatings based on VK8 alloy were obtained on the cutter body of a road milling machine. Recycling of cutter tip waste was carried out by applying wear-resistant coatings to the cutter body of the KZTS A6/20 by the electrospark alloying method. It was found that the hardening coating does not have pores, cracks and other defects, its main elements are Fe, W, Mn, Cr, O. The microhardness of the coating is 1.6 times higher than the microhardness of the substrate. When scratched, the coating on the samples wears off, but there are no delaminations, that is, it is destroyed by the cohesive mechanism.

Conclusion. The completed study will allow developing recommendations for the practical application of resource-saving technologies for the restoration and strengthening of road milling cutter bodies and implementing the recycling process.

The purpose of the study is to establish the dependence of the electrical resistance of iron powder on the compression force.

Methods. The electrical iron powder was placed in a sleeve. The sleeve is tightly closed on both sides by metal pistons protected from external sources of electrical resistance by dielectric spacers. A force F̅ is applied to one of the spacers. The strain gauge measures the amount of applied force, and the ohmmeter records the presence of electrical resistance and its amount in the circuit section. Using this setup, a full factorial experiment was conducted, during which the powder samples were changed, a 7-gram sample was taken, as well as a 14-gram sample, and the above parameters were monitored. In this case, the change in electrical resistance was chosen as an optimization criterion when assessing electrical conductivity in a circuit section.

The results of the study showed an empirical dependence of the resistance of electrical iron powder on the change in pressure on it, by conducting a full factorial experiment. Thus, for the first time, new dependencies of the electrical resistance of iron powder on the compression force were obtained. This dependence shows that of the three factors under study, the greatest influence is exerted by the compression force, with an increase, the resistance decreases, a decrease in resistance is also observed with an increase in the bushing diameter, which models the diameter of the conductor cross-section. With this increase in the mass of the powder, the resistance increases, from which it can be concluded that with an increase in the length of the conductor, the electrical conductivity decreases.

Conclusion. As a result of the experiments, it was found that the electrical iron powder changes its electrical resistance depending on the force applied to it, the diameter of the conductor and the mass of the compressed powder. Based on the results of the experiment, an empirical relationship was compiled between these factors.

The purpose of this work was to study the fire resistance of technical materials treated with flame retardants based on electroerosion powder of Aluminum hydroxide.

Methods. Aluminum metal wastes of the AD0E brand were dispersed in distilled water at a loading weight of 250 g at an experimental installation. The resulting electroerosive aluminum powder was studied by various methods. The microanalysis was performed on a QUANTA 600 FEG microscope. The phase composition was studied using a Rigaku Ultima IV diffractometer. The fire resistance of the treated fabric was studied according to the following method: a strip of fabric 5 cm wide and 10 cm long was suspended in an upright position by one end in a tripod clamp (the other end remains hanging freely). The flame of an alcohol burner was placed under the lower end of the sample for 12 seconds (according to a stopwatch). After the specified time, the flame of the burner was removed and the burning and smoldering time of the sample was noted after the flame ceased to act. Gorenje After the end of the experiment, the area of the charred part of the sample was measured.

Results. Experimental studies of the fire resistance of textile materials treated with flame retardants have shown high efficiency of using an electroerosive aluminum hydroxide powder for these purposes. Aluminum hydroxide powder was obtained in distilled water from electrical aluminum metal waste. The peculiarity of the use of the obtained aluminum hydroxide is due to the fact that it provides a difficult-to-ignite fabric, reduces the ability of the material to ignite, localizes the flame; provides a long-term flame retardant and at the same time antiseptic effect; treated fabrics are odorless, harmless to humans and animals; consumption for impregnating fabrics: 100-250 g/m², depending on the density of the fabric.

Conclusion. The effectiveness of flame retardants based on electroerosive Aluminum hydroxide powder is confirmed by the fact that cheap metal waste and progressive environmentally friendly (without wastewater and emissions), low- energy technology (up to 5 kWh/kg) are used for its production.

Purpose. Experimental evaluation of the thickness of the protective shell thickness of magnetite colloidal particles representing a single molecular layer of oleic or erucic fatty acids.

Methods. Experimental data were obtained by independent measurement of three volumetric concentrations (magnetic, solid and hydrodynamic) of magnetite particles in magnetic liquid using magneto-granulometric analysis, density measurement and titration of pure carrier liquid during peptization of dry sediment of particles. The experimental data were processed by numerical solution of the system of nonlinear equations describing the additivity of volume, mass and magnetic contributions of stabilized colloidal particles and carrier liquid to the volume, density and saturation magnetization of polydisperse magnetic liquid, respectively.

Results. Four samples of magnetic liquid differing in the disperse composition of magnetic nanoparticles, three of which were stabilized by oleic and the fourth by erucic fatty acids (surfactants), were experimentally investigated. The samples were prepared by titration of pure carrier and peptization of dry sediment of colloidal particles prewashed from free surfactant molecules. For each sample, the density and magnetization curve were measured and magneto-granulometric analysis was performed. The data obtained by different methods agree with each other provided that the thickness of the nonmagnetic layer on the surface of magnetite particles is equal to 0.76 nm and the effective length of the oleic and erucic acid molecules is equal to their maximum possible values in the fully straightened state.

Conclusion. At stabilization of magnetite particles by unsaturated fatty acids, the double bond, providing bending of these molecules in the basic energy state, does not play an essential role, since the thickness of the protective shell, equal to the effective length of surfactant molecules, is equal to their maximum possible length in the straightened state.

Purpose of the work: to study the influence of interparticle dipole-dipole interactions on the susceptibility of a magnetic fluid stabilized by a double layer of surfactant in water.

Research method consists in measuring the initial differential susceptibility of a magnetic fluid depending on its concentration. Three samples of fluid based on magnetite particles, differing in the composition of the stabilizing shells, were studied. The following acids were used as the first layer of the stabilizer: lauric (C12), decanoic (C10) and octanoic (C8). The second layer of the stabilizing shell was formed by sodium dodecyl sulfate with a small proportion of the corresponding acid. Susceptibility measurements were performed on a setup for measuring magnetization curves. The concentration of the samples was determined by their saturation magnetization.

Results. The concentration dependences of the initial susceptibility were measured for three samples of magnetic fluid based on magnetite particles. The obtained results were compared with theoretical models of the modified effective field of A.O. Ivanov and the average-spherical one. Both theories predict overestimated values of susceptibility in relation to experimental values. The modified effective field theory overestimates the results by 20%. The mean-spherical model - by 12%. It is shown that the correct interpretation of the concentration dependence of the susceptibility of magnetic fluid samples is possible only by approximating the ratio of susceptibility to saturation magnetization. Based on this approximation, an empirical formula in the form of a third-degree polynomial with a negative cubic term is proposed to describe the concentration dependence of susceptibility.

Conclusion. Thus, the obtained results require the construction of new or modification of old theories of dipole-dipole interaction of magnetic particles in aqueous colloidal solutions with stabilization of particles by a double layer of surfactant.

Purpose. Investigation of the characteristics of polyamide fabric modified with Boron nitride nanoparticles and evaluation of its filtration properties.

Methods. The Raman scattering spectra were measured using a scanning Raman microspectrometer OmegaScope AIST-NT in ZXXZ̅ geometry (λ = 532 nm, W = 25mW) with a spectral resolution of 3 cm^-1. The crystalline structure was studied using X-ray diffraction on a GBC EMMA diffractometer (Bragg-Brentano scheme, A = 0.154 nm, step size 0.02°). The filtration properties of the polyamide fabric were investigated using an SF-2000 spectrophotometer in the spectral range of 450-750 nm. The modeling of the interaction between the modified polyamide fabric and inorganic solution molecules was carried out using the Materials Studio 2020 software package with the Forcite module.

Results. In the spectra of Raman scattering and X-ray diffraction patterns of fabric modified with Boron nitride nano-particles, peaks were identified at 1360^-1 cm and 2θ = 27.32. The size of the coherent scattering regions was 0.65 nm, which corresponds to the doubled interlayer spacing of Boron nitride. The change in optical density of the filtrate through the fabric was ΔD = 0.04, corresponding to a 9.6% increase in transparency. Quantum-mechanical modeling showed that van der Waals forces act between the iron hydroxide molecules and the fabric, while chemical bonds exist between the Iron hydroxide and the Boron nitride nanoparticles.

Conclusion. Modification of polyamide fabric using the Langmuir-Blodgett method results in a more intense spectral profile for ordered coatings, while the immersion method with ultrasonic dispersion is suitable for bulk coatings, allowing nanoparticles to penetrate the fabric structure. These results are confirmed by X-ray diffractometry. The effectiveness of Boron nitride in improving the adsorption characteristics of polyamide fabric is also demonstrated.

Purpose. To investigate the influence of magnetic field on the elastic characteristics of isotropic magnetic elastomer.

Methods. The behavior of magnetic particles in the sample was studied based on the idea of a hierarchical model of chain formation combined with a lattice model of particle arrangement. When studying systems with chain aggregates, a statistical distribution function was introduced for the number of particles in a chain, which made it possible to calculate the number of chains in a composite with a given particle concentration. The nonlinear magnetization of particles in the sample was modeled in the form of the semi-empirical Frohlich-Kaenely law, which made it possible to calculate the magnetization of materials with good accuracy, both in weak and strong magnetic fields.

Results. The paper presents a model describing the elastic properties of an isotropic magnetic elastomer synthesized without the effect of a magnetic field. The elastomer consists of particles with a volume concentration of 28.6%, capable of magnetization, the size of which is 10 microns. These particles are embedded in a polymer matrix. Under the action of a magnetic field, chains of magnetic particles are formed in the polymer. It is assumed that the length of such chains is less than the size of the sample in the direction of the field. The dependences of the shear modulus of the composite on the external magnetic field are determined.

Conclusion. A physical model is proposed that successfully predicts the magnetorheological effect in the studied composite material with a soft matrix and randomly distributed particles synthesized without a magnetic field. The research is based on an improved lattice theory that takes into account the probabilistic distribution of particles due to the polymerization process of the composite. A hierarchical principle of forming particle chains is proposed, where their number doubles at each stage. It has been established that chains of such length make the main contribution to the macroscopic shear modulus of the composite. The agreement between theoretical results and experimental data confirms the adequacy of the proposed model for describing the behavior of a magnetic elastomer in an external magnetic field.

Purpose of research. Fixation of Boron nitride nanoparticles on polyamide fabric.

Methods. Colloidal systems were stirred and dispersed in an ultrasonic bath QUICK 218-35 with an emitter power of 50 W and an ultrasonic technological disperser “Volna” UZTA-0.4/22-OM. The activation of the polyamide fabric surface and its cleaning were carried out by plasma treatment in a low-pressure PICO system. Deposition of nanoparticles using the Langmuir-Blodgett method was performed on a KSV Nima 2002 setup. The morphology and elemental composition of the polyamide fabric before and after the application of boron nitride nanoparticles were studied using a JEOL 6610LV scanning electron microscope equipped with an Oxford Instruments X-Max energy-dispersive X-ray analyzer. The research methodology included the use of a low-vacuum mode, which was important for preventing the accumulation of surface electrical charge on dielectric samples.

Results. Sediment-resistant colloidal systems were synthesized based on boron nitride nanoparticles stabilized with stearic acid and an aqueous solution of Boron nitride nanoparticle powder with the addition of an oiling agent. Nano-particles from the first colloidal system were deposited on polyamide fabric using the Langmuir-Blodgett method, while nanoparticles from the second system were applied by immersing the fabric in the system with ultrasonic dispersion. SEM images of the polyamide fabric and its energy-dispersive analysis confirm the uniform fixation of boron nitride nanoparticles on the fibers by these methods.

Conclusion. In this work, boron nitride nanoparticles were fixed onto polyamide fabric using the Langmuir-Blodgett method and by immersing the fabric in a colloidal system with ultrasonic dispersion. This allowed for uniform deposition of nanoparticles both on the surface of the polyamide fabric and between the fibers, enhancing its performance characteristics.

Purpose of the study. To characterize the size composition, atomic and electronic structure, and antioxidant activity of Cerium dioxide nanoparticles synthesized by the hydrothermal method in an autoclave.

Methods. Cerium dioxide nanoparticles were synthesized in an autoclave at 150°C. The size composition of the nanoparticles was characterized by small-angle X-ray scattering diffractometry. The structural and phase composition was studied using X-ray diffractometry. Scanning electron microscopy with an energy-dispersive X-ray analysis attachment was used to analyze the elemental composition of the samples. Antioxidant activity was studied in the photochemical degradation reaction of methylene blue dye under irradiation with a diode source with a wavelength of 660 nm. The residual concentration of methylene blue in the process of photodegradation was determined using spectrophotometry.

Results. Pure Cerium dioxide nanoparticles measuring 10-25 nm were synthesized using hydrothermal synthesis in an autoclave at 150°C. In the presence of the obtained cerium dioxide nanoparticles, the process of photodegradation of the methylene blue dye under the influence of red laser radiation slows down by 80%. The addition of ammonium citrate-stabilized Cerium dioxide nanoparticles leads to a slowdown in the process of photodegradation of methylene blue under irradiation with red light due to antioxidant activity, which increases with increasing concentration of nanoparticles. Maximum antioxidant activity is manifested at a molar ratio of ammonium citrate to CeO₂ of no more than 2:1.

Conclusion. The hydrothermal synthesized CeO₂ nanoparticles stabilized by ammonium citrate exhibit pronounced antioxidant activity. The results obtained can be used to develop selective antitumor photosensitizers based on Cerium dioxide nanoparticles.

Purpose of research. The aim of the work was to select conditions for the quantitative spectrophotometric determination of phosphorus in archaeological finds made of Iron using reducing agents - ascorbic acid and Mohr salt.

Methods. A fragment of a cast-iron object discovered during archaeological excavations in the Salovsky settlement on the territory of the Penza region was chosen as the object of research. Reagent preparation and spectrophotometric analysis of phosphorus content were carried out in accordance with GOST 2604.4-87 Alloyed cast iron. Methods for the determination of phosphorus. To assess the reliability of the results, errors were identified according to the Smirnov criterion, and to assess the accuracy of the results, the variance, standard deviation and relative standard deviation of the determination of phosphorus content were calculated. To identify the effect of the reducing agent on the results of phosphorus determination, a one-factor analysis of variance was performed.

Results. In the course of the work, the conditions for dissolving the samples were selected: the weight of the sample, the required volume of nitric acid, dilution of the samples, the volume of reagents for analysis. An experiment aimed at searching for a reducing agent of the yellow phosphorous-molybdenum complex has demonstrated satisfactory results when using the Mohr salt. The adequacy of replacing ascorbic acid with Mohr salt is proved by the close values of the phosphorus content in the studied samples: using the ascorbic acid reducing agent, the phosphorus content was (1.74.0.15)%, and using Mohr salt (1.72.0.24)%.

Conclusion. The results obtained during the study allow us to conclude that the Mohr salt can be used as a reducing agent in the determination of phosphorus in the form of blue heteropolycomplex in iron alloys.

The purpose of the work was to study the influence of polycyclic structure as an additive on thermodynamic parameters of dyeing systems. The dyeing process of cotton textile material using direct dye was investigated.

Methods. Various methods were used in the experimental studies to achieve the objective. Physical methods were used to study the properties of dyeing solutions. The quality of fabric preparation was evaluated by capillarity value. IR and UV spectroscopy methods were used to study the solutions. Cross sections of the stained materials were studied using the microscopic method. The methods defined for this type of products were used to evaluate the quality of coloring resistance to physicochemical and physical-mechanical influences.

Results. The process of dyeing of cotton textile materials with direct turquoise lightfast dye in dyeing solutions containing classical components of dyeing formulation and in solutions with 1,2,4-triazine additive is considered. Kinetic dependences of the content and sorption of direct turquoise lightfast dye by cotton textile material under the investigated conditions have been obtained. A comparative study of the resistance of the obtained color of cotton material to various types of chemical and mechanical influences was carried out.

The results obtained during dyeing with a direct turquoise light-resistant dye in the presence of a triazine functional additive show that not only chemical intensification of the coloring process is observed, but also a change in the color stability to certain types of influences.

Conclusion. It is revealed that the introduction of polycyclic structure in the form of 1,2,4-triazine additive into the dyeing composition has a positive effect on the process of sorption of direct turquoise lightfast dye by textile materials of cellulose nature and increases resistance to various kinds of physical-chemical and physical-mechanical influences.