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Vol 40, No 3 (2019)
- Year: 2019
- Articles: 13
- URL: https://ogarev-online.ru/1068-3666/issue/view/14183
Article
Studying Nanotribological Properties of Functional Materials via Atomic Force Microscopy
Abstract
Abstract—Nanotribological tests via atomic force microscopy were optimized by recording the lateral interaction forces between the probe tip and the sample surface in the contact mode. In the case of thin film metal materials, the technique enabled us to determine independently the sliding force and the static friction force, which reduced the measurement error of tribological characteristics at the nanoscale by 3—5 times.
201-206
Evaluating the Applicability of Electrodeformation Placing Technology by a Flexible Tool for Chromeing Hydrocilindes
Abstract
Abstract—The results of comparative triboengineering tests of chromium coatings formed using electroplating deposition and electrodeformation cladding with a flexible tool (EDCFT) are given in this work. In the formation of coatings by the EDCFT method, sintered bars of chromium powder doped with additives of ultradispersed diamond graphite mixture (UDGM) and thermally expanded graphite were used as coating materials (donors). It has been established that, when rubbing without a lubricant, sprays of rubber on the surface of specimens with a coating with the lowest values of the coefficient of sliding friction fsl and total weight wear Δm have samples with chromium coatings formed by electroplating (ftr = 0.37, Δm = 0.2 × ten–3 d) using the EDCFT method from a donor doped with the ultradispersed diamond-graphite mixture UDGM (ftr = 0.35, Δm = 0.23 × ten–3 d). Bench tests of hydraulic cylinders with full-scale stock samples with a coating formed by the EDCFT method from chromium doped with UDGM have established full compliance of the prototypes of hydraulic cylinders with the specifications.
207-212
Surface Parameters with Different Treatment Technologies and Their Effect on Wear
Abstract
Abstract—This work obtained profilograms of the subroughness of friction surfaces for two types of finishing treatment: fine grinding and ion implantation. The average values of the subroughness step along the midline and the subroughness height of 10 points have been calculated. It has been shown how the surface subroughness changes during ion implantation. It was found that the surface subroughness changes only slightly after the wear tests. The parameters of the subroughness of the friction surface are given, which are preferable from the point of view of reducing wear for selected test conditions.
213-217
Selection of Materials of Friction Lining Centrifugal Brake Rollers
Abstract
Abstract—The results of friction-wear tests of rolled friction-polymer materials (FPM) of two types using the operating modes of the friction brake of a centrifugal type roller are presented in this work. The tests were performed on the Nanovea T50 tribometer according to the pin-on-disk scheme. Experimental dependences of temperature, coefficient of friction and wear on the pressure on the friction lining have been obtained. The stability of the coefficient of friction of the FPM/Steel friction pair was evaluated. Comparison and analysis of the results have been performed and recommendations on the application are presented.
218-222
Modeling the Hydrodynamic Friction Mode on Amsler Type Friction Testing Machines
Abstract
The technique of modeling the hydrodynamic mode using Amsler type friction testing machines has been developed, approved, and introduced into the practice of tribological research. It has been established that at certain values of diametric gap the roller–elliptic shoe friction couple may be replaced by the roller–circle shoe friction couple. The dependence between the gap values in circle and elliptic shoes has been theoretically obtained. A shoe holder design has been proposed which ensures full contact with the cylindrical surface of the roller and significantly reduces the time needed for tests and increases their accuracy.
223-228
Powder Bearings with Polymer Inserts
Abstract
This work considers the design of a support slider bearing based on macro-composite material—a powder composite with polymer inserts—intended for operation in self-lubrication mode. The problems of the starting condition are solved in this work based on the implementation of the rotaprint principle by placing on the friction surface in the conical cavities of polymer inserts. The ratio of the areas of polymer, the lubricating element, and the metal surface was optimized in the work—as a result of which the amount of optimal value of the coefficient of relative area for the investigated range of design parameters of the bearing was 0.45 ± 0.05. The multifactor planning of experiment was used in this work to determine the optimal value of topology coefficient and to construct a regression model. The design of the support slider bearing was tested with a T-11 model precision tribometer.
229-233
Phase Composition, Mechanical and Tribological Properties of Ti–Al–N System Coatings Deposited by Vacuum-Arc Method
Abstract
The results of the phase composition, mechanical and tribological properties of the vacuum arc (Ti,Al)N coatings using separated plasma flows are presented in this work. It has been determined that the formed Ti–Al–N coatings are of a nanoscale structure and characterized by high hardness and resistance to deformation, low friction coefficient. This allows for the use of such coatings for products operating under conditions of increased abrasive and adhesive wear.
234-238
Improving Wear Resistance of Fast-Cutting Steel R6M5 after a Volume Pulse Laser Strength
Abstract
Abstract—This work studies the influence of mechanical properties on the durability of cutting tools made of high-speed steel R6M5 under production conditions and their relationship with indicators of changes in the “defectiveness” of the structure (density of dislocations, size of mosaic blocks, crystal lattice microdistortion), which occurred as a result of a single exposure to a high-energy laser pulse. It is shown that when assigning optimal modes of volume pulsed laser hardening (VPLH) (energy and duration of a laser pulse, laser beam diameter, distance from the irradiation point to the main cutting edge), the results of X-ray analysis can be used, which can significantly improve the technical and economic indicators of the hardening and operation of cutting tools made of high-speed steel Р6М5 in terms of productivity, prime cost and instrumental costs of laboratory research.
239-243
Calculating the Friction Force at Rest in Joints of Similar Hardness Assembled with Tightness
Abstract
The dependencies for determining the axial frictional force at rest in cylindrical joints assembled with a thermal tightness at different hardness ratios of the materials of the parts were investigated in this work. It is shown that the values of the friction coefficient may significantly differ depending on phenomena occurring in the contact of the microroughness of the mating rough surfaces of the parts. The obtained dependence for the determination of the friction force was experimentally proved. The application of the developed method for determining the friction force at rest allows reliable values of the bearing strength of the pressure joint to be obtained and reveals the unused reserves of the bearing strength. The developed method may be used in the design of pressure joints.
244-249
Markovian Chain Theory Application for the Description of Wearproof Powder Coating Profile under Sliding Friction
Abstract
A statistical approach is proposed based on the Markovian chain theory to describe the coordinate distribution for the profile of powder coatings under sliding friction. Transitional probability matrices are constructed for homogeneous Markovian chains corresponding to a stage of steady-state-state wear of powder coatings. Calculated and experimental data concerning the friction surface profiles of wear-resistant coatings are analyzed. It is shown that the proposed approach simplifies the calculations upon processing a large amount of profilometric data to predict the wear and microgeometry of the friction surfaces of powder coatings.
250-257
Modeling of Stationary Frictional Heating of a Coated Body
Abstract
A model of stationary friction heating of a coated body is proposed in this paper and a discrete contact for periodically located circular areas is considered. The elastic properties of materials are assumed to be temperature independent in the considered temperature range. The stress-strain state of the coating is considered to be known from the solution of the contact problem for a two-layer elastic base. Relations for calculating the temperature distribution in the surface layer and the base in the vicinity of a separate asperity taking into account the effect of neighboring asperities were obtained. As an example, we calculated the temperatures for a ceramic coating obtained by micro-arc oxidation and deposited on an aluminum alloy substrate. The results can be used to predict fracture upon frictional loading of coated bodies.
258-265
Research on the Effect of Lanolin on Rheological and Tribotechnical Characteristics of Complex Calcium Grease
Abstract
The rheological and tribological characteristics of greases based on a complex calcium thickener using lanolin as an antifriction additive were studied in this work. An increase in the rheological characteristics, a decrease in wear and a coefficient of friction, depending on the lanolin content in the lubricant, is shown, and its optimal concentrations have been determined.
266-269
Applying Anisotropy to Lubricant Oil Fluorescence to Evaluate Its Physical and Chemical Properties
Abstract
The development and improvement of fluorescent methods for controlling the working properties of a lubricant in tribosystems is an urgent matter. A method for measuring the decay kinetics of the lubricant fluorescence anisotropy of lubricating oil on a FL900 CTD high-speed fluorometer (Edinburgh Analytical Instruments) in the single-photon counting mode is described in this work. Measurements of the attenuation time of fluorescence anisotropy of new and mineral-oil working in hydraulic systems were made. A correlation was established between the decay time of the fluorescence anisotropy of oils and the product of the dynamic viscosity of the oil and the volume of the fluorescent complex, which can be used in laboratory analysis of the performance of oils, and also in creating methods and devices for on-line diagnostics of friction units.
270-275