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The article proposes and justifies the use of technological methods of improvement of nanodispersed magnetic oil lubricating properties. It is shown that if the ferrofluid oil producing process includes additional operations, which are aimed at the removal of excess surfactant stabilizer and big magnetic agglomerates from its composition, it allows decreasing friction and wear of lubricated surfaces by tens of percent. The authors have chosen ferrofluid lubricant oil that had been synthesized based on dioctyl sebacate for the research due to its good lubricating properties, low volatility and viscosity and a wide temperature range of operability. To remove the excess of the surfactant stabilizer dissolved in a ferrofluid oil dispersion medium the dispersion medium replacement method proposed by R.E. Rosenzweig was used. To remove large magnetic units from magnetic fluid the authors used magnetic separation. In boundary friction surfaces lubricated by ferrofluid oil there might be their abrasive wear by agglomerates from single-domain magnetic particles. In this connection, the article experimentally proves the necessity of modifying magnetic liquid unit friction surfaces using MAO-technology to protect them from abrasion wear.

The article presents experimental data on the influence of the roughness and the load on the mechano-chemical processes at the boundary sliding friction. It was found that the use of electrometric method for assessment of the mechano-chemical processes occurring in the frictional contact area allows one to determine the duration of plastic and elastic-plastic deformation and the electrical conductivity, and the product of these indicators was suggested to be taken as a criterion for anti-wear properties of lubricants allowing to estimate their propensity to form protective boundary layers.

The paper deals with the design of the bearing assembly slide bearing crank pin of the crankshaft of boosted diesel engines. Selecting bearing diametrical clearance is an important matter in the design of the bearing assemblies. Then the assigned values clearances are checked with the help of the bearing and oil consumption hydrodynamic parameters of calculations. The magnitude of the clearance is one of the main indices. The final selection of clearance magnitude is carried out after the experimental operation or special experimental studies in case the latter is done.

The research and development results of new anti-friction polymer nanocomposites based on polytetrafluoroethylene characterized with an increased wear resistance due to the polymer matrix with complex fillers-modifiers modification are presented in the paper. Fillers include micro- and nanoscale components of different nature and the particles geometry having specific surface and surface free energy high values. These factors provide the polymer matrix high-performance structural modification and significant increase in nanocomposites wear resistance in dry boundary friction.

The use of diamond-like carbon (DLC) coatings in engine components can be one of the potential solutions for automotive industry to improve fuel efficiency by controlling the friction and wear. The tribological behavior of various types of DLC coatings in liquid lubricated systems and their interaction with lubricants are needed for proper usage of these coatings. In this study, the friction and wear performance of four different DLC coatings in synthetic base oil polyalpha-olefin (PAO) were investigated using pin-on-disc tribometer under boundary lubricated condition. One hydrogen-free ta-C DLC, one hydrogenated a-C:H, one silicon doped a-C:H:Si and one chromium doped a-C:H:Cr were deposited on SUJ2 bearing steel pins and discs for this study. The structural, mechanical and topographical characterizations of these films were analyzed using Raman spectroscopy, Nano indenter and Atomic Force Microscopy (AFM). The results indicate that structure and doping elements greatly affect the tribological performance of DLC coatings. Ta-C coatings gave the lowest boundary friction, while Si-doped a-C:H:Si showed the highest boundary friction. Hydrogenated a-C:H coating exhibited the highest wear rate, but silicon and chromium incorporation in a-C:H coatings greatly increased the wear resistance. Cr-doped a-C:H:Cr showed the lowest wear rate, followed by Si-doped a-C:H:Si coating.

The paper suggests the results of numerical investigations of flow cooked fluid in the crescent-shaped microgap of oil-free bearing turbo pumps working in conditions of boundary friction. As a result we managed to identify determining constructional parameters of channels leading cooling medium.

The experimental dependencies of the friction coefficient and the wear rate for lubricants without additives and the oil containing an anti-wear additive are obtained. The received laws cannot be explained with the hydrodynamic theory of greasing, theories of boundary friction or their combination. To eliminate these contradictions we offer a rheological model of a lubricant including the dependence of viscosity on a thickness of the lubricant layer.