Introduction. The development of modern equipment and technologies for geological exploration and mining processes raises the problem of ensuring the reliability and durability of mechanic units operating under the conditions of elevated temperatures and pressures in the presence of aggressive external environments. In this regard, there is a need to create functional coatings with unique physical, mechanical and operational properties.Aim. To improve the performance of electrospark coatings based on an analysis of a cause-andeffect diagram and a regression study of the technological modes of processing steel units of geological exploration equipment (on the example of hydraulic cylinder rods of drilling pumps).Materials and methods. To harden the steel surfaces of hydraulic equipment parts, the technology of electrospark deposition (ESD) was used on an IMES-1001 mechanized installation using carbide electrodes and various gas media. In order to identify causal relationships between the factors affecting the hardened surface and to establish the most important factors affecting the quality of the formed coating, the Ishikawa diagram method was used and a regression analysis was performed. The adhesion activity of the obtained coatings was assessed by atomic force microscopy on a Solver PRO scanning probe microscope in a semi-contact air scanning mode using NSG10probe sensors with a resonance frequency of 219 kHz and a radius of curvature of the probe tip of 10 nm. When determining the strength of the adhesive interaction of the probe and the surface at one point, the absolute error was 15 nN. Tribological tests were carried out on a 2070-СМТ-1 standard friction machine according to the “disk-shoe” scheme.Results. The obtained cause-and-effect diagram showed that the technological modes of an electrospark deposition installation comprise a determining factor affecting the quality of the formed layers and coatings. In order to identify those process parameters that had the greatest effect, a regression analysis was carried out. The capacitance of the unit capacitors was found to have the greatest impact on the adhesion force formed by the ESD coating. Therefore, in order to reduce the strength of the adhesive interaction of surfaces and, as a result, increase their wear resistance, it is necessary to increase the capacitance of capacitors while reducing the voltage and processing time when implementing the ESD technology. On the basis of tribological tests, it is concluded that the minimum wear rate of coatings can be obtained by alloying the steel surface in an oxygen environment with a carbide electrode based on tungsten carbide with additives of elements that form unlimited solid solutions with the surface material and perform the role of fluxes (Ni-Cr-B-Si).Conclusion. Due to strict requirements to the performance of metal surfaces of units that enter into frictional interaction during the implementation of mining and exploration processes, there is a need to improve existing technologies for creating functional (wear-resistant) coatings.

. Problem Statement (Relevance). The paper is relevant because it presents the development of a thermodynamic approach to managing the processes of the structural modification of surface and near-surface layers during the formation of nanostructured topocomposites. The main problem is the need for developing theoretical approaches applied to get a target control over the layer-by-layer ion-vacuum modifying processing, when creating nanostructured topocomposites. Methods Applied . The ideas of the structural-thermodynamic approach developed by the authors to the analysis of plasma processes are a theoretical basis of the study. Experimental results were obtained using methods of ion-plasma and ion-beam processing, as well as ion assistance with cascade cross effect. To apply an intermediate oxidized layer, the authors used such surface chemical modification methods as oxidation and passivation. We also used the methods of electron microscopy, probe microscopy, and scratch testing of the samples to study the morphology and adhesive properties of the coating-interface-base systems. Originality . We have developed a structural thermodynamic model that reveals the nature of modification effects in the coating-interface-base system at the micro-, submicro- and nanostructural levels caused by ion-plasma flows. The connection between thermodynamic parameters and technologi-cal modes of ion-vacuum treatment has been established to control the processes of the structural modification of surface and near-surface layers. The formation of quasi-wave multimodal nanostructures was detected. Result . The thermodynamic analysis of the structural modification showed that the formation of the gradient structure of topocomposites was determined by activation structural processes and controlled by the density of the energy flow and the reaction of the material to it, and dissipative ones by the intensity of energy and mass transfer in the modified surface of the material. The defining characteristic of forming the type of structural-phase states and their extent (depth) in the coat-ing-interface-base system is energy imbalance between activation processes determined by a degree of ion-vacuum effect and dissipative phenomena of structural relaxation of the base material. Practical Relevance . The results of the structural and thermodynamic analysis of modification processes allow us to purposefully form various types of gradient topocomposites with a given structure and composition of coatings, interface and near-surface layers of the base material.

ФОРМИРОВАНИЕ НАНОСТРУКТУРНЫХ ТОПОКОМПОЗИТОВ С КЛАСТЕРНО-ГРАДИЕНТНОЙ АРХИТЕКТУРОЙ КОМБИНИРОВАННОЙ ИОННО-ВАКУУМНОЙ ОБРАБОТКОЙПолещенко К.Н. 1 , Коротаев

The wear resistance and wear characteristics of cluster-gradient architecture (CGA) nanostructured topocomposites are studied. The specifics of tribocontact interaction under microcutting conditions is considered. The reasons for retention of high wear resistance of this class of nanostructured topocomposites are studied. The mechanisms of energy dissipation from the tribocontact zone, due to the nanogeometry and the structural-phase structure of CGA topocomposites are analyzed. The role of triboactivated deformation and diffusion processes in providing increased wear resistance of carbide-based topocomposites is shown. They are tested under the conditions of blade processing of heat-resistant titanium alloy.

Based on the justified methodological complex the study of the multilevel structural state of coatings and surface layers created by the ion-plasma modification was made. A comparative quantitative assessment of structural changes and the chemical composition of coatings by SEM, XPS, EDX methods and the physical and mechanical properties of coatings based on titanium nitride was carried out. It was found that for all variants of coating formation there is no titanium in the metallic state and, therefore, the formation of a droplet phase does not occur. Layer-by-layer XPS analysis has determined that coatings are heterogeneous in its composition in depth. It is shown that the modification of steel surfaces with a TiN-based composition can be used to form wear-resistant coatings on the working bodies of road milling machines that are actively used in the overhaul and maintenance of the highways.

The morphology, composition, and chemical state of coating elements based on titanium nitride (TiN) formed by the method of condensation with ion bombardment at different modes on Hadfield steel substrates (110G13L grade) have been studied by the methods of SEM, EDX, and XPS. It has been established that, in the formed coatings, the highest titanium content was in the composition of nitride and oxynitride, whereas there was also a certain amount of titanium and titanium oxides chemically bonded to carbon. It has been shown that titanium in the metallic state was absent for all the studied modes of coating formation and, therefore, the drop macrofraction formation did not proceed at these conditions. XPS layer-by-layer analysis demonstrated that coatings had a heterogeneous composition over depth. The microhardness of samples was studied by the Vickers test. The highest microhardness values were observed for the samples with coatings formed for 35 and 50 min, presumably as the result of higher content of compounds of the TiN(x)C(y)O(z)type with higher hardness than that of TiN.

The article updates the long-range action effect in the formation of nanostructured topocomposites under the conditions of the ion-plasma impact. The authors study the features of the concentration dependences of the distribution of elements in the boundary layers in the formation of the two-layer system "film-base". They determine that under the conditions of the implementation of the cascade cross-effect at considerable depths in the material of the hard-alloy base, locally inhomogeneous areas are formed, resulting in an increase in the microhardness of the material. Within the framework of the worked out simulation model, the study of factors contributing to the manifestation of the long-range action effect is undertaken. The contribution to the change of concentration dependences of the temperature, different diffusion mechanisms and the pressure gradient is established and differentiated. Based on the synthesis and analysis of the dynamics of the competing processes of "deceleration - acceleration" of the diffusion, the explanation to the formation of the hardened sublayers in the hard-alloy base of topocomposites and their role in the manifestation of the long-range action effect is offered.

The article considers the wear resistance and wear peculiarities of nanostructured topocomposites with the clustered gradient architecture. The authors regard the specificity of the impact of the cluster morphology on the contact interaction under microcutting conditions. They study the causes of persistence of the high wear resistance for the given class of nanostructured topocomposites. The mechanisms of energy dissipation from the tribocontact zone due to their nanogeometry and the structural-phase structure are analyzed. The contribution of triboactivated diffusion and deformation processes to providing the increased wear resistance of topocomposites on the hard-alloy basis is differentiated. Their approbation in the conditions of edge cutting processing of heat-resistant titanium alloy is carried out.

The topic of the study of the long-range effect in the formation of nanostructured topocomposites under conditions of ion-plasma exposure is updated. The features for the concentration dependences for the distribution of elements in the surface layers during the formation of two-layer film—base system are studied. It is established that under the conditions of the cascade crossover effect at significant depths, the formation of locally inhomogeneous regions occurs in the material of the carbide base, which leads to increase in the microhardness of the material. Within the framework of the developed simulation model, the contribution to the change in the concentration dependences of temperature, various diffusion mechanisms, and the pressure gradient contributing to the manifestation of the long-range effect is established and differentiated. Explanation of the formation of hardened sublayers in the carbide-based topocomposites and their role in the manifestation of the long-range effect is given based on generalization and analysis of the dynamics of competing processes of braking—accelerating diffusion.

Abstract The main aim of this work was to study the morphology, elemental and quantitative composition, as well as the chemical state of titanium nitride coatings obtained by condensation with ion bombardment on substrates of sintered hard alloy (VK8: WC – 92%, Co – 8%) and Hadfield steel (110G13L: Mn – 11-14.5%, C – 0.9-1.3%). Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were used to analyze the structure and composition of the coatings. It was established that the composition of coatings formed on different substrates at the same deposition time is almost identical and consists of TiN, TiNO, and TiC. This indicates that coating formation conditions are reproducible. At the same time, it was shown that in the coating formed on 110G13L steel, an increase in the amount of titanium oxy nitrides is observed, associated with the peculiarity of the occurrence of nonequilibrium processes in the preparation of coatings. It was shown that the application of the approach based on the use of XPS and EDX data obtained from various depths makes it possible to correctly study the composition of coatings based on titanium nitride and future control their composition by changing the parameters of coating formation.

The article proposes an improved system of ion-plasma modification based on the use of three cathodes installed at different angles. Using the methods of scanning electron microscopy and energy dispersion analysis, the authors study the morphology, the composition of elements and the coating structure in terms of titanium nitride formed by ion-plasma modification with a change in processing time. They find that there is no drop phase of metallic titanium, adversely affecting the mechanical properties in the coating formed on the studied technological regimes of ion-plasma processing. An experimental assessment of the destruction of nanostructured ion-plasma coatings on the structural parts of pipeline fittings operating under fretting corrosion is carried out.

This article presents the effect of the substrate on the morphology and chemical composition of titanium nitride coatings formed using the condensation with ion bombardment method. Various steels, sintered hard alloy (tungsten carbide - 92%, cobalt - 8%) and titanium-based alloy were used as substrates. The paper presents the XPS data obtained at various depths from the surface. The article also presents the data of the wear resistance of coatings for road milling cutters.

The work presents a methodical complex of studies of base metal and its coating composition, that allows to study the change in structural characteristics of material at micro-level, mezzo-level and macro-level. The effect of changes in structural state on the properties of coatings and base materials during treatment of cast iron parts working surfaces by air plasma spraying (APS) was established. Physico-Mechanical properties of coated samples and the features of their structure formation has been evaluated during experiments. An optimal composition of a powder mixture containing self-fluxing solid alloys and wear-resistant fillers, which provides enhanced performance in conditions of hydroabrasive wear is proposed. It is established that plasma spraying of the coating (65% PR-NH17SR4 + 35% KHNp-30) with subsequent heat treatment and reflowing leads to an increase in wear resistance up to 1.5-2 times.

The article proposes an approach to solving the problem of increasing fretting resistance of lock joints of blades for gas turbine engines through the creation of nanostructured topocomposites with the surface layers in a metastable state having a low shear stability in terms of vibrofriction. The authors implement the method of vacuum combined ion-plasma processing, which allows forming the surface layers of the material with mixed amorphous-nanocrystal structure and purposeful controlling the surface morphology. They show that the proposed flow diagram allows developing the required morphology from the arrays of nano-sized conglomerates of the “asperity – cavity” type on the surface. A comparative study of fretting resistance of nanostructured topocomposites in terms of vibrofriction is carried out. It is established that the specificity of their wear is to reduce the wear rate at the initial stage.

The article considers physico-technological aspects of receiving nanostructural topocomposite coatings in terms of the cascade cross effect based on the special cathodic system, making possible ionic-plasma processing simultaneously with the use of three cathodes in a pulse mode. The authors carry out theoretical and experimental researches of forming concentration profiles of element distribution in surface layers of the bilayer "film-base" system. They determine the features of mass transfer processes developing in response to cascade cross effect. It is demonstrated that due to the mutual diffusion of the film and the base elements in the field of the phase boundary in the "film-base" system a transition area is formed. Its dimensions can be associated with the thickness of the nanofilm. The authors give an example of receiving a multilayer nanostructural composition in terms of cascade cross effect.

The main objective of this paper was to study the morphology, composition and chemical state of coatings based on titanium nitride obtained using the condensation method with ion bombardment. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) were used to analyse the structure and composition of the coatings produced at different formation times. It was determined that coatings formed at different times still have a suffi ciently close chemical composition and contain titanium nitride (TiN), titanium oxynitride (TiNxO1–x), titanium oxide (TiOx) and titanium carbide (TiC). The paper demonstrates that the increase in the formation time of coatings leads to a decrease in the proportion of carbon in the amorphous state and an increase in the fraction of carbon which is a part of titanium carbides. In the composition of coatings formed in 15 and 50 minutes, the fraction of carbon chemically bonded to titanium differs by a factor of two. The XPS analysis with the Ar+ ion sputtering showed that the coatings have an uneven distribution of elements in depth. It is demonstrated that with the increase in etching time, a signifi cant decrease in the total carbon concentration in the coating is observed. At the same time, the proportion of carbon chemically bonded to titanium increases. It was also found that the TiN decreases, while the amount of TiNxO1–x and TiOx increases. Basing on the data obtained, we propose descriptions for the dynamics of diffusion of carbon and oxygen and the formation of carbides, oxynitrides, and titanium oxides during the formation of coatings.

The article regards formation processes of activation and dissipative energy flows under ion-plasma sputtering of coatings. It proposes an advanced system of ionic-plasma processing with the activation of the processed surface by high voltage pulses of electric potential. The authors carry out the experimental evaluation of tribological properties for the samples with coatings and study the features of their surface damage. It is established that the topokompozitny coverings, containing high-disperse nanodimensional clusters reduce probability of brittle destruction during an initial stage of operation of tribocouplings. They show that the use of high-frequency pulse oscillations under ion-plasma sputtering decreases friction ratio and increases wear resistance of coatings.

С применением экспериментальных методов анализа исследованы морфология, элементный состав и химическое состояние элементов покрытий на основе нитрида титана, формируемых методом конденсации с ионной бомбардировкой. Установлено, что покрытия с различным временем формирования обладают достаточно близким химическим составом и содержат нитрид (TiN), оксинитрид (TiNxO1-x), оксид (TiOx), карбид титана (TiC). Однако с увеличением времени формирования в покрытиях наблюдается повышение доли углерода, входящего в состав карбида титана. На основе анализа состава покрытий, полученных при различной длительности формирования, а также данных об изменении состава покрытий по глубине предложена возможная динамика внедрения и диффузии примесей (углерода и кислорода) в процессе формирования покрытий. Авторы выражают благодарность Ивлеву К. Е. за проведение исследования образцов методом SEM, а также руководству ОмЦКП СО РАН за предоставление оборудования для исследования образцов методами SEM и EDX. Работа выполнена при финансовой поддержке Минобрнауки РФ в рамках государственного задания, проект № 11.11760.2018/11.12.