The aim of this work was to analyze the wear resistance of composite ion-plasma coatings and substantiate methodological approaches for its prediction. The object of the study was multilayer 2D-nanocomposite coatings of the TiN/AlN system with a total thickness of 0.8—4.0 μm. The coatings were applied using vacuum ion-plasma technology onto a substrate made of 40CrNiMo structural steel with a sorbite structure and a hardness of HRC 28—30. Within each nitride layer, the composition of the components was close to equiatomic, and for the coating as a whole it was Ti:Al:N = 1:1:2 (at. %). The structure of the coatings, the morphology of the friction tracks and the wear mechanisms were studied using high-resolution scanning electron microscopy. The mechanical characteristics of the coatings (hardness H and elastic modulus E) were determined using standard continuous indentation techniques. The tribological characteristics (friction coefficient m and volume wear J) were determined using the ball-on-disk sliding friction test with a circular trajectory of the indenter ball. The analysis of the obtained experimental data made it possible to construct a dependence of the coating hardness on their elemental composition and showed that the mechanical characteristics and wear resistance of the coatings sprayed at a lower temperature of 300—350 °C are consistently higher than those sprayed at 400—450 °C. In addition, it was found that the highest wear values ​​J were observed for the coatings with the smallest thickness. In order to analyze the effect of the coating thickness d on their wear resistance, a computational and analytical model for predicting coating wear during tribological tests was used. On its basis, diagrams of critical states of ion-plasma composite TiN/AlN coatings were constructed, which made it possible to calculate the critical value of the coating thickness d_min, at which the mechanism of coating wear during friction changes. With a relatively thin coating (d < d_min), located on a “softer” (plastic) substrate, during tribotesting, accelerated wear of the coating occurs by the abrasive-mechanical mechanism due to the deflection of the coating and its subsequent cracking, peeling and chipping. With a relatively thick coating (d ³ d_min), wear occurs by the abrasion mechanism, which, with high hardness of the coating, is characterized by its significant wear resistance and significantly extends the service life.

The aim of the work is to identify the most effective conditions and modes for the synthesis of Mo–S–Ti–C coatings on titanium alloy VT5, providing the best tribological characteristics.

The coatings were applied by vacuum arc evaporation of cathodes on a modernized NNV-6.6-I1 installation. The cathodes were produced using self-propagating high-temperature synthesis. Assistance to the gas discharge plasma during coating application was provided by an autonomous plasma source with a heated cathode. In this case, the bias potential on the substrate, the deposition time, and the composition of the working gas environment — argon and/or a mixture of argon and nitrogen in a ratio of 1:1 — were varied.

It has been established that the use of assisting action of gas discharge plasma on deposited coatings provides a 2—3 times increase in their hardness. Using energy-dispersive X-ray spectroscopy, the presence of both sulfide-forming elements (Mo, S) and elements capable of forming solid carbides (Ti, C) was revealed in the evaporated cathodes and in the applied coatings. X-ray structural analysis confirmed the synthesis of compounds of the Mo₂S₃ and TiC type in both cathodes and coatings. In the most effective version of a three-layer coating using, along with argon, additionally nitrogen in gas discharge plasma, the formation of a strengthening phase TiN was also recorded. Tribological tests were carried out under friction conditions without lubricant. It was established that the most effective version of a three-layer coating with the addition of nitrogen in a gas discharge plasma, compared to the initial VT5 alloy, showed a decrease in the friction coefficient under a load on the counterbody of 1 N — by 2 times, under a load of 5 N — by 3 times; the wear rate in both cases decreased by an order of magnitude or more. Thus, the presented technological method ensures the formation of a gradient-layered coating architecture and appears promising for industrial application.

The aim of the work is to study the effect of sliding velocity on the evolution of the subsurface structure and tribooxidation in a high-speed steel coating reinforced with WC after friction on a steel counterbody without a lubricant.

In this work, we studied the tribological behavior of electron-beam composite coatings obtained from a mixture of R6M5 powder steel and WC in contact with a counterbody made of SHH15 steel. It was found that the structure of the coatings is a matrix based on γ+α' iron, reinforced with skeletal structures of eutectic carbides. A simultaneous decrease in the friction coefficient and wear rate of the coatings with an increase in the sliding velocity from 0.8 m/s to 3.6 m/s was obtained. This is due to the tribochemical formation of iron tungstates FeWO₄ and Fe₂WO₆ at sliding speeds of 2.4 m/s and 3.6 m/s, which then allows the formation of a surface mechanically mixed layer, which, in addition to the said iron tungstates, includes fragments of carbides and metal particles of the coating matrix. Such a friction surface structure provides a solid lubrication effect and protects the underlying coating structures from destruction. The specificity of such an adaptation mechanism is that it is realized at relatively low sliding speeds, which corresponds to the maximum calculated flash temperature of about 290 °C. The discovered tribological adaptation mechanism should contribute to the successful use of electron-beam composite coatings WC/tool steel in various industries.

Copper samples of M1 with different structural states were obtained by equal-channel angular pressing and subsequent annealing. The structure of the samples before and after sliding friction tests was studied by transmission electron microscopy and metallography. The mechanical characteristics of the samples were determined during tensile tests and nanoindentation. During friction according to the ball-on-disk scheme, the friction coefficient, vibration and acoustic emission were recorded to identify the features of the influence of the structural state of the material on the friction dynamics. Confocal laser scanning microscopy was used to assess wear.

It was found that an increase in the number of ECAP passes and annealing have an insignificant, no more than 8 %, effect on the sliding friction coefficient in the steel—copper pair. It is shown that an increase in the number of ECAP passes can reduce the wear of M1 copper by 26—93 %. After annealing at a temperature of 200 °C, wear is additionally reduced by 5—8 %, compared to samples without annealing. Annealing at 300 °C leads to an increase in wear by 37—65 %, compared to samples without annealing. Low plasticity and high hardness of the material in a highly deformed state lead to the formation of a thick surface layer consisting of a mixture of oxidized wear particles, copper oxides and fragments of the destroyed friction surface. Annealing at temperatures of 200 °C and 300 °C contributes to less pronounced destruction of the surface of the samples, as well as oxidation and mixing with wear particles in a thinner surface layer. The results obtained in the work indicate a significant effect of the structural state on both the mechanical properties and the features of the sliding friction and wear process of M1 copper.

The material deformation mechanisms governing concrete strength in building structures exhibit inherent complexity. Due to the physical characteristics of concrete composites, frictional parameters demonstrate interdependent relationships during material-structure interactions rather than maintaining complete independence. The interfacial transition zone between materials and substrate structures undergoes constrained deformation under parent material confinement, inducing modified physical properties in near-interface regions. This phenomenon reveals material heterogeneity through differentiated responses to intrinsic and extrinsic factors, where the relative dominance of these influences ultimately dictates structural performance metrics.

The aim of the work is to construct a microscopic model to investigate the frictional properties of interlayer interfacial concrete in building structures under cyclic coupling effect. The main particular emphasis focuses on elucidating the mechanical behavior of materials subjected to cyclic loading conditions.

This investigation employs an enhanced Alternating Direction Method of Multipliers (ADMM) algorithm to systematically extract characteristic features and correlation attributes from diverse material specimens. Through the implementation of penalty factor constraints and uncertainty quantification protocols, the methodology effectively reduces prerequisite assumptions while distinguishing variable functional relationships. Microstructural modeling analyses integrated with experimental validation confirm the technical feasibility and innovation superiority of the proposed approach. Comparative evaluations under cyclic coupling conditions reveal critical advancements in three dimensions: resistance potential under load cycling, frictional behavior under varying loading rate responses, and multi-parametric physical property enhancements. The developed technique has demonstrated superior concrete performance enhancement compared to conventional strength improvement methods. It also effectively restrains the expansion of stress damage and strengthens the stability and safety of the foundation structure under the condition of cyclic coupling.

The analysis of the structural model of composites developed for the case of dispersion of fillers in the polymer melt is carried out, it is shown that the use of the expression for determining the matrix loading characterizing the share of external applied load falling on the matrix is not effective enough for comparative assessment of wear resistance of developed composites at the same concentrations and average sizes of dispersed fillers, but consisting of different materials. For the possibility of a refined assessment of wear resistance of such composites an additional criterion taking into account the energy characteristic of interaction between matrix and filler at the molecular level is proposed. Computer modeling of the molecular structures of polyetheretherketone and its two nanoscale composites containing fullerene and nanoscale copper was carried out to determine the shear modulus and intermolecular interaction energies in the volume of the materials under study and at the matrix—filler interface. It is noted that the introduction of nanoscale fillers increases the values of shear modulus and volumetric energies of intermolecular interaction. At the same time, the most significant increase, by more than 2.5 times, was noted in the value of the energy of intermolecular interaction at the interface of the matrix—filler phases in a composite containing nanosized copper, compared with a composite containing fullerene. Thus, this parameter is proposed as an additional parameter for assessing the wear resistance of nanoscale composites at the stage of their development.

A common defect of springs is a decrease in their wear resistance due to changes in the mechanical properties of the wire along its length, particularly the yield strength, including during friction during operation of the spring. According to the springs stress-strain state presented mathematical model, the wire yield strength changes effect on springs wear resistance during contact hardening is investigated. The residual springs deformation dependence graph on the yield strength of its material for different wire diameters is constructed. Dispersion of the spring wire yield strength in the coil according to state standards 9389 “Carbon steel spring wire” can be up to 200—250 MPa. It is established that in this case, the manufactured springs deformation dispersion will amount to 11.76 % and exceed the permissible values. For first precision group springs, the permissible deviations for deformation dispersion are ± 5%, for second precision group springs — ± 10 %. The wire change in the yield strength effect graph along the length on the dispersion of spring deformation for a load of 140F₃ (F₃ is spring compression force when coils come into contact) is constructed. Using the presented technique and taking into account the dispersion of spring deformation depending on the change in the wire along the length yield strength, including due to friction during operation, it is possible to significantly reduce the percentage of defects in the manufacture and increase helical cylindrical compression springs wear resistance.

Studying the content of ferromagnetic wear particles in used motor oil allows us to judge the degree of wear of the rubbing parts of the engine. This paper describes a new method for determining the fractional composition of a system of ferromagnetic wear particles in used motor oil, based on the kinetics of particle sedimentation in a gravity field and the instrumental time of transverse relaxation of NMR protons of hydrocarbons in a polydisperse suspension. Unlike traditional sedimentation analysis by continuous weighing, the proposed method uses a method of continuous measurement of the NMR relaxation time T₂*. It is assumed that suspended particles increase the non-uniformity of the magnetic field of the relaxometer magnet and the apparatus time of spin-spin relaxation proportionally to the mass of the sediment.

An analytical expression for the particle size distribution and for the most probable equivalent radius for a mathematical model of the sedimentation curve is obtained. Two physical models of iron particles of different sizes introduced into fresh motor oils are investigated. It is shown that at the same iron concentration in engine oil, small particles make the magnetic field more non-uniform than large particles. The kinetics of changes in relaxation times T₂^* during sedimentation is studied. It was found that during sedimentation of ferromagnetic particles, the times of spin-lattice T₁ and spin-spin T₂ relaxation remain unchanged. To obtain the distribution of ferromagnetic particles, all necessary transformations of the data array T₂^*(t) were performed numerically. It is shown that, in contrast to the unimodal distributions for model samples of fresh oils with iron particles, M-10G2CS oil used for 420 hours gives a distribution in a wide range of radii from 3 μm to 11 μm. The distributions of particle radii in Shell Rimula 15W40 oils used for 250 hours and 500 hours are, as expected, similar, but the percentage content of fractions in the oil used for 250 hours is less than in the oil used for 500 hours. The nature of these distributions is different from that of M-10G2CS oil (420 hours). The capabilities of the proposed method for highly dispersed systems are limited by the very slow settling of nanosized particles in a gravitational field.

The results obtained in this work can be useful for dispersion analysis of any organic suspensions containing microsized ferromagnetic particles.

Currently, the quality of an abrasive tool is assessed, as a rule, directly in the production conditions of the consumer's enterprise, which is associated with methodological difficulties, time costs and often insufficient objectivity of control, due to the impossibility of analyzing a large sample of test circles. The lack of modern methods and means of technology control in the manufacture of tools does not guarantee the stability of its quality, including in terms of wear resistance, which determines the durability and grinding coefficient of the wheel.

The purpose of the work is to find the possibility of express quality control of an abrasive tool made of electrocorundum material according to the criterion of relative wear resistance.

Tests were carried out and the results of wear resistance and energy efficiency of grinding various samples of abrasive wheels using the counterbody abrasion method were obtained.

It is shown that the use of the upgraded Shlif-3 device allows for express quality control of the abrasive tool, including determination of relative wear resistance. A correlation has been established between this indicator and the operational and technological characteristics of the instrument.