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The investigation results of the structure and wear resistance of composite chemical coatings on the nickel base obtained by means of mutual codeposition with nanodispersed particles of aluminum oxide and potassium polytitanate are presented. The investigations are carried out by scanning electron microscope. It is found, that composite nickel penetrates into the base metal to a depth of about 5 µm, forming diffusion layer, which provides an increased cohesive strength of the coating with base metal. Composite coating has abundance of inclusions of different size along the whole surface; which are absent in the base coating. Nanodispersed particles penetrate into the coating; accelerate the nickeling process, which provides the increase of the coating wear resistance.

The article presents the results of the investigations on the development of new method of hardening and reconditioning of resource-determining parts of hydraulics aggregates of various purpose machinery by composite electroless nickel coatings. It is proved, that by obtaining the composite chemical coatings the most efficient are nanodispersed particles of aluminum oxide and potassium polytitanate. The tribological testing testified, that the wear of the samples which were deposited with the nickel based composite coating, is 1.4 times less than the wear of the samples with the base nickel coating. The bench testing determined that in spool and sleeves of the hydraulic distributors hardened by the composite electroless nickel deposition, leakage value is 1.4 times less than in commercial ones, and 1.3 times less compared with the pairs being reconditioned by ironing.

The article presents the results of research on the establishment of an effective nanoscale phase and modes of applying nanocomposite electroplating coatings based on chromium. As a result of the conducted studies, it was found that it is advisable to use a nanodispersed aluminum oxide powder as a nanoscale phase. The method of mathematical planning of the experiment was used to determine the optimal modes of coating and the concentration of nanoscale particles in the electrolyte. The microhardness of the obtained coatings was chosen as an optimization parameter, since it significantly affects their wear resistance. The highest microhardness of a nanocomposite electrolytic coating based on chromium is achieved when the electrolyte is heated to a temperature of 50 °C, a current density of 59 A/dm2 and a concentration of nanoscale phase particles in the electrolyte of 3.2 g/l, which ultimately corresponds to an increase in microhardness to 14.32 GPa. It is also established that nanocomposition coatings have a positive microhardness gradient in thickness, which allows leveling the difference in the values of the microhardness of the coatings and the base metal and will help to increase the adhesion strength of the coatings to the base on the one hand and their wear resistance on the other. Based on the microhardness measurements of chromium-based nanocomposition coatings, statistical series were formed. 30 samples were subjected to measurements. According to the results of microhardness measurements, the average square deviation of the values of nanocomposition coatings based on chromium was 0.05 (coefficient of variation 0.283). To equalize the obtained experimental microhardness information, the law of normal distribution is chosen, since the coefficient of variation, according to which the greatest probability of microhardness values of nanocomposite coatings based on chromium is observed in the range of 14.32–14.37 GPa.

Studies of sedimentation stability have shown that for additives containing smaller particles of powder components (30…50 nm) it is 1.32 times higher than for additives containing larger particles of powders (50…300 nm). The analysis of the experimental results showed that the modification of Lukoil 10W - 40 engine oil with the addition of L-60 brass powder with a particle size of 30...50 nm contributed to a 1.21-fold reduction in friction torque compared to Lukoil 10W–40oil mixed with L-60 brass powder with a particle size of 50...300 nm and 1.38 times compared to the base oil Lukoil 10W–40. The wear of samples (pads) after 3 hours of testing on base oil Lukoil 10W - 40 is 11.6 times greater compared to the wear of samples operating on Lukoil 10W–40oil with the addition of L-60 brass powder with a particle size of 50-300 nm. The test result of Lukoil 10W - 40 oil with the addition of L-60 brass powder with a particle size of 30-50 nm showed an increase in the mass of the friction sample (pads) by 0,3 mg. The addition of L-60 brass powder with a dispersion of 30...50 nm (2nd sample) to the base oil, after 3 hours of testing, led to a decrease in the temperature of the friction surface of the samples by 11  and 16% compared to the first sample (Lukoil 10W–40+ brass L60 (50 ... 300) and to the third sample (Lukoil 10W–40), respectively.