Antifriction Coatings Research Articles

Formation of film antifriction coatings on the friction surfaces of machine parts

The article presents a study of the adhesion strength of film anti-friction coatings. The process of a film anti-friction coating formation is described. An experiment to determine the adhesion strength of a film anti-friction coating is considered. In the course of the experiment, a number of samples of different roughness were used on which an anti-friction coating was applied. The thickness of the coating was controlled by a thickness gauge. Conducted a qualitative assessment of the adhesive strength of the coating with the base metal. Conclusions about the strength of adhesion, its dependence on surface roughness and initial surface treatment are made.

Tribological Wear-Preventive Coatings

This article discusses wear-preventive tribological coatings that increase the operational life of artillery, tank, and rifle barrels. Studies have been conducted using some of them. The presence of a sufficiently large scientific and technical reserve in the field of material science of heat-resistant alloys and antifriction antiwear coatings is noted.

Увеличение ресурса подшипников на газовой смазке судового энергетического оборудования с помощью антифрикционных покрытий

Увеличение ресурса подшипников на газовой смазке судового энергетического оборудования с помощью антифрикционных покрытий

MATHEMATICAL MODELING OF MODERN ANTIFRICTION POLYMERS BEHAVIOR

An physicomechanical properties experimental study of the modern antifriction materials number was performed as part of the work. The 6 polymers and composites based on them having the greatest prospects for use as antifrictional coatings and interlayers in contact nodes are selected. The materials showed a nonlinear deformation behavior model in experimental study of samples. Therefore, the deformation theory of elastic-plasticity for the active loading case is chosen to describe the material behavior model in the framework of the first approximation. A numerical model of deformation of cylindrical samples under constrained compressionan experiment has been constructed. The optimal finite element mesh with a gradient decrease in the element size to the contact area of the cylindrical samples with the press plates has been selected. As part of the numerical experiments series, it was established: samples deformations from modern antifriction composite materials by 25–30 % more than other polymers considered, with one level of contact parameters; the modulus of the maximum contact tangential stress of all the materials examined is on average 25 times lower than the contact pressure.

ИССЛЕДОВАНИЕ АДГЕЗИОННОЙ ПРОЧНОСТИ ПЛЕНОЧНЫХ АНТИФРИКЦИОННЫХ ПОКРЫТИЙ

The paper is dedicated to the investigation of adhesion strength in film coatings. The goal of the work is a qualitative estimate of the strength of film antifriction coatings applied on friction units of machines. The topicality is grounded by the fact that the friction decrease on surfaces in units ensures the increase of life, power effectiveness and reliability of machinery. 
 Most of the works are dedicated to the study of manufacturing films, their phase composition, structure, stress-strain properties, whereas in the material offered the adhesion properties of film antifriction coating are emphasized, which is a sufficient novelty. 
 During the investigations of the adhesion strength of antifriction film coatings there was used a method of a normal detachment. To carry out comparative tests there were prepared four groups of different antifriction coatings. For each coating under testing there were prepared five samples which were loaded with the smooth increase of a breaking tension. 
 Therefore there are obtained experimental dependences of normal stresses (σ) upon relative elongation (ε), which allow using values obtained for surfaces coated with antifriction film coatings with different areas. Upon completion of coating tests both parts of the samples tested were subjected to visual analysis. In the course of the analysis a character of destruction was defined. As a result of the theoretical and experimental investigations carried out there were drawn conclusions describing a qualitative and quantitative estimate of the adhesion strength of antifriction film coating.

Technology of applying antifriction coatings using an electric arc pulsating power

The coating of a mechanical mixture of metal powders and solid lubricant material is due to difficulties due to the low adhesive and cohesive strength of the resulting coatings. This problem can be avoided when using in the process of the pulsating power electric arc (PPEA). The object of research in the paper is an anti-friction coating based on ΠΓ-XH80CP3 powder with the addition of 20% by volume of graphite ΠΓ-50, of which plasma coating using PPEA gave a coating with friction coefficients fmp min = 0.038 and fmp max = 0.062 under contact load of 300 MPa. The test results of a friction pair, carried out for 500 hours on a path of friction of 55,000 m, showed the stability of the friction coefficient within fmp = 0.056 … 0.061. The application of the coating process using the surface activation of the PPEA allowed us to obtain high-strength anti-friction coatings with the content of a solid lubricant element in the coating composition up to 20% of the total coating volume.

Technological Parameters of Production and Properties of Babbit-Based Composite Surfacing Rods and Deposited Antifriction Coatings

A method for production of Sn–Sb–Cu alloy (babbitt) based composite coatings reinforced with micron-sized SiC and B4C particles on a steel substrate has been developed. A combined action of uniformly distributed high-modulus reinforcements and plastic matrix increases the strength and durability, reduces the wear rate, and significantly improves the antifriction properties of the coating. The surfacing rods based on B83 babbit containing reinforcing particles for arc welding of coatings on steel substrate were produced by the extrusion method. These rods were characterized by lack of porosity and discontinuities in the internal volume as well as by defect-free surface. The density and hardness of the rods are comparable with the same characteristics of the cast babbitt. Arc welding of coatings was performed in the AC mode with a non-consumable tungsten electrode in an argon atmosphere. Welding current I = 160–170 А, arc voltage U = 16–18 V, welding rate Vw = 4.2 m/h, and protective gas (Ar) flow rate VAr = 12–14 L/min. The structure and tribological properties of the composite rods and coatings deposited were investigated with the help of electron and optical microscopy methods and under dry sliding friction tribological tests. The size of SnSb intermetallic compounds in the rods after extrusion and in the coatings deposited was determined. It was found that the size of intermetallic phases decreased by a factor of two after introduction of SiC and B4C particles into the babbitt alloy. The results of wear tests show that reinforcing and modifying the structure of the surfacing rods by introduction of high-strength micron- and submicron-sized ceramic SiC and B4C particles improves the antifriction properties of surfaced composite coatings. The friction coefficient of the composite coating was the same throughout the load interval, while for the unmodified babbit coating its value was by two times higher than that for the composite coating under a load up to 39 N and 20% higher under loads greater than 39 N. The coatings with high-strength SiC and B4C particles have a low coefficient of friction (0.4) and a high coefficient of the friction process stability (0.8).

Механізм утворення антифрикційних покриттів фрикційно-механічним методом

Different interpretations of the mechanism of formation of antifriction coatings by a friction-mechanical method hinders the widespread use of finishing antifriction non-abrasive treatment in the manufacture and repair of parts. It has been established that at the initial stage, the application of an antifriction coating by a friction-mechanical method will be accompanied by a process of micro-cutting of an antifriction material with its subsequent filling of the micro relief cavities in the form of chips. The fulfillment of the condition of micro-cutting of antifriction material is obligatory for the preparation of anti-friction coatings. A theoretical scheme of the process of micro cutting during the formation of an antifriction coating has been developed. The peculiarities of filling the micro relief cavity with antifriction material have been investigated. Taking into account the studied consistency, a new scheme for the application of anti-friction coatings with high tribological parameters has been proposed.

Evaluation of the Friction Coefficient of Antifriction Coatings Based on Ti-Cu Obtained by the Ion-Plasma Deposition in Vacuum

Ion-plasma antifriction coatings based on Ti-Cu were deposited by the method of ion-plasma sputtering in vacuum with the aim to gain a coating with a low coefficient of friction. To protect steel part from wear intermetallic, nitride and conglomerate coatings based on Ti-Cu with thickness of the coating h ≈ 2-5 μm obtained at different regimes of deposition. Thickness of the antifriction coatings and proportion of the chemical composition varied by deposition time, voltage and current of the magnetron, current of evaporators, pressure of gas in a vacuum chamber. This paper presents the results of the tribotest carried out on CSM Instruments pin-on-disk type tribometer. Comparing with uncoated samples microhardness and roughness of the coated samples increased two to three times, coefficient of friction of coated samples was twice lower.

НЕКОТОРЫЕ АСПЕКТЫ ЭФФЕКТИВНОСТИ НАНЕСЕНИЯ АНТИФРИКЦИОННЫХ ПОКРЫТИЙ ТЕХНОЛОГИЯМИ ФИНИШНОЙ АНТИФРИКЦИОННОЙ БЕЗАБРАЗИВНОЙ ОБРАБОТКИ

The article analyzes the effectiveness of anti-friction coatings obtained by finishing anti-friction non-abrasive treatment (FANT), including processing in metal-clad technological media, in order to improve the performance of machine parts. The analysis of the application of coating technologies FANT on materials operating at elevated temperature and at high pressure, as well as with high values of energy fluxes in the environment, was carried out. The results of the application of various compositions of cladding elements and FANT technologies for various engineering products are presented. The results of studies of the use of FANT technologies developed with the participation of the authors confirm their high efficiency for improving the wear resistance of artillery gun barrel materials. Decrease in wear ranging from two to three times compare to regular technology. Field testing of anti-friction anti-wear coatings, carried out by specialists of the FSE SRI «Geodesia», confirmed the prospects of this direction for increasing the survivability of artillery barrels.

Experimental Studies of Wear Resistance of Anti-Friction Coatings of Bimetal Fluid-Film Bearings

The paper presents experimental results of wear resistance measurements of anti-friction coatings of bimetal fluid-film bearings. As a result, nature and peculiarities of wear process of anti-friction coatings and steel base have been identified. An analysis of antifriction properties of studied copper-based coatings is presented. The paper also features recommendations for application of the studied coatings obtained by means of gas-flame spraying.

Adhesive strength research of film antifriction coatings

Abstract The article presents a study of adhesion strength of thin anti-friction coatings. Performed formulation of the research problem, taking into account the qualitative and quantitative strength of anti-friction coatings. The stages of the experiment are described. Four film anti-friction coatings are selected. Each coating was applied to five experimental samples. It is proposed to conduct experiments on a universal machine IR5047-50. A number of qualitative and quantitative estimates were obtained in the form of the dependences of normal stresses on the relative elongation of the film anti-friction coating. Presented conclusions on strength of anti-friction coatings.

Development of the Composition and Modes of Spraying Antifriction Coating Reinforced with Quasicrystals for the Manufacture of Sliding Bearings

The paper presents the compositions of coatings from composite materials reinforced with quasicrystals. The composition and mode of application of cold gas-dynamic deposition of antifriction coating based on composite materials reinforced with quasicrystals for the manufacture of sliding bearings have been determined and determined. Quasicrystals of the Al-Cu-Fe system, metal composite coatings based on copper reinforced with quasicrystal line particles were used for research. In the course of the work, the compositions of quasicrystal-reinforced coatings were developed, the optimal composition and modes of applying the coating by cold gas-dynamic spraying were determined. According to the optimal mode, samples were made and their mechanical and tribological properties were investigated.

Development of a Heavy-Loaded Hydrodynamic Slide Bearing for a Reducer for a Turbojet Dual Engine

The object of the design is a heavy-loaded hydrodynamic slide bearing for the reducer for a turbojet bypass engine (TJBE) of a new generation for the near-medium-haul main plane (NMHMP) of civil aviation. The aim of the work is to produce working design documentation (WDD) for sliding bearings with anti-friction coatings based on metal polymers, porcelain polymers, composite materials using quasicrystals and developing variants of design and structural schemes for using sliding bearings with anti-friction coatings based on metal polymers, ceramic ceramics or composite materials with using quasicrystals in satellites (gears) of fan reducers of the family are promising TJBE for NMHMP. Designed bearings are designed for use as supports for the intermediate gears of the gearbox, made according to the kinematic scheme Star. Based on the calculations, the design of the sliding bearing was determined and the WDD was produced for four bearings of the same size with different antifriction coatings used as supports for intermediate gears of the designed TJBE for NMHMP. But, as experience shows, in order to successfully work out the parameters of promising heavily loaded hydrodynamic sliding bearings, a close relationship is needed between the calculated estimate and its experimental verification (while perfecting the tools and methods of both). As a result of this work, WDD was produced for sliding bearings with anti-friction coatings based on metal polymers, ceramic ceramics (silicon carbide, titanium diboride) with and without quasicrystals and composite materials (titanium carbonitride, silicon carbonitride) with and without quasicrystals.

Forming of Porous Composites with Ti Powder by Self-Assembly of Particles in Polymer Suspensions for Creating Functional Materials

Porous composites on the basis of natrium-carboxymethylcellulose polymer with Titanium powder and AlOOH nanoparticles as a modifier were developed. Morphology of formed structures was examined using REM methods. Influence of AlOOH additives upon suspension surface properties was researched. Evaluation of components interaction power in systems was done; values of wetted angle of contact, adhesion work, cohesion work and work of wetting energy in suspensions were calculated. Peculiarities of self-organization in composition systems with Ti and AlOOH particles were studied. Order strength in the system was evaluated with the help of selective Shannon entropy. The correlation of the smallest Shannon entropy variability with forming relatively homogeneous pores was revealed. Combinations of components proportions within the system with Ti powder and AlOOH nano-sized particles filling, which provide generation of homogeneous pores with the size of ≈250 µm under the temperature of 55°C, were defined. The developed materials may be used as reinforcing elements, sorbents, abrasives, antifriction coatings provided that the matrix pores are filled with lubricants.

Formation the structure of porous carboxymethylcellulose films for developing materials with antifriction properties

Abstract Composite porous films have been developed on the basis of sodium-carboxymethyl cellulose polymer. It is stated that boehmite films with ordered pores are formed during the process of modification of aqueous solutions of Na-carboxymethyl cellulose by high disperse boehmite particles under the temperature of 50 °C. Sizes of generated pores reach 600–800 µm. Using infrared spectroscopy is was found out that phase composition of porous compositions remains unchanged in the process of formation. The possibility of producing antifriction coatings at the expense of filling the pores with pyrolytic graphite as hard lubricant is shown.

Повышение ресурса осевых газовых подшипников с антифрикционным покрытием на основе плазменного электролитического оксидирования: физический эксперимент

Повышение ресурса осевых газовых подшипников с антифрикционным покрытием на основе плазменного электролитического оксидирования: физический эксперимент

Development of the composite material and coatings based on niobium carbide

We investigated the structure of composites based on the system NbC with a copper bond, obtained by impregnating the porous carbide skeletons with a metallic melt in a vacuum. In order to receive a porous skeleton, the powder of NbC, the average size of ~1 μm, was mixed on a 5 % solution of rubber in gasoline. After drying, the mixture was ground at a sieve into granules, which were pressed into briquettes of dimensions 55×30×10 mm. To ensure the intensification of the process, as well as wetting, impregnation was carried out at a temperature of 1,400 °C. The result was the obtained material with a fine-grained two-phase structure.The microstructure was investigated using a method of scanning electron microscopy (SEM), the chemical composition ‒ applying a method for energy dispersion analysis (EDS).The hardness was measured by Rockwell (scale C), the fracture toughness ‒ by the indirect Evans-Charles method.The composite's structure consists of rounded grains of NbC, which form a continuous skeleton, and the layers of copper bonding. The average size of grains and the intragrain layers of bonding is 1.8 μm and 1.1 µm, respectively.An analysis of the interaction zone between NbC and Cu via EDS method revealed the presence of a 0.5 μm thick zone of diffusion, resulting from the redistribution of Nb and Cu by limited solubility. The presence of the diffusion zone makes it possible to provide a solid interphase bonding and, accordingly, the high level of mechanical properties. The hardness and fracture toughness of the obtained material are 40 HRC and 24 MPa×м1/2, respectively.Given the phase composition and properties of the developed composite, it is recommended to apply it as an alternative for composites of the system WC‒Cu in the form of a monolithic material or coatings. A coating was applied using the method of electric-spark doping, using the manual installation MP-EL2. The coating's thickness is 30 μm, microhardness is ~500 MPa, and the friction coefficient against steel without lubrication is 0.04.The designed materials are recommended for use in friction pairs in the form of a monolithic material, or anti-friction coatings

Evaluation of the Physical and Mechanical Characteristics of Ion-Plasma Antifriction Coatings Based on Ti-Cu

A modern method of processing steel parts by ion-plasma sputtering in vacuum is proposed as a solution to the problem of friction and wear. An ion-plasma coating based on Ti-Cu has been developed. Such parameters as microhardness, roughness, friction coefficient of the intermetallic, conglomerate and nitride coatings have been studied

Varying of Oil Consumption of Fluid-Film Bearing’s Surface Layer by Means of Application of Anti-Friction Coatings

Gas flame spraying is the most accessible method of gas-thermal spraying. Pores are formed on the inner surface of the bimetallic fluid-film bearings as a result of the application of anti-friction coating on the steel substrate. The presence of such pores, the "microfibre effect", affects positively on life expectancy of fluid-film bearings. The study of the oil consumption of anti-friction coatings allows recommendation of these coatings for using in the manufacturing process of bimetallic fluid-film bearings.