The dissertation presents a solution of an important scientific and practical problem of establishing mechanisms of frictional interaction of contact surfaces under the action of corrosion and hydrogen factors, the solution of which expands the understanding of tribocorrosion mechanisms, which allows a scientifically well-grounded approaching to choose methods to improve tribopairs.
The method of measuring the electrode potential in tribocorrosion studies using a capillary probe was improved, which made it possible to more accurately assess the potential of different sections of the friction track and undeformed surface.
An empirical relationship between the width of the friction track in tribocorrosion and the polarization current at the corrosion potential has been established, which makes it possible to quickly assess the degree of its wear by the electrochemical properties of the friction pair.
It is established that the ratio between the values of corrosion potential, tribopotential and freshly renewed surface potential can be used to assess the frictional properties of secondary structures and the wear mechanism, in particular the D16T alloy The dual effect of cathodic polarization on the tribocorrosion of D16T alloy and steel 08Х18Н10Т is shown: reduction of corrosion rate and fracture inhibition at the potentials below the juvenile surface potential and increase of corrosion-mechanical wear during hydrogen depolarization. Anodic polarization intensifies the formation of secondary structures and increases wear. The coefficient of friction decreases insignificant. It was shown for the first time that the frictional interaction under anodic polarization initiates the shift of the pitting potentials of the 08H18H10T alloy towards the corrosion potential.
It is established that the parameters of fine crystalline structure, phase composition and micromechanical properties of surface layers of metals change due to electrolytic hydrogenation, which determine their tribological behavior and wear mechanisms.
It was found that galvanic composite coatings Ni-P and Ni-B after heat treatment reduce wear of steel 17Mn1Si in 2-5 times in a hydrogen environment and wear of aluminum alloy Д16T in a chloride-containing environment in ~ 7 times. It has been shown for the first time that the combined action of hydrogenation and friction accelerates diffusion processes in an amorphous Nickel-phosphorus coating, which promotes the formation of a reinforcing phase of Ni3P in the surface layers, which increases its wear resistance.
It is shown that the high corrosion resistance and hardness of the coatings deposited by the plasma powder method do not determine their corrosion-mechanical wear resistance. The corrosion resistance of coatings based on iron, nickel and iron-nickel increases in corrosive environments with increasing pH, increases, but their tribocorrosion resistance decreases by 25-30%, which is determined by the nature of secondary structures in the friction zone.
It was found that the addition of graphite (2-4%) to the BH20 composite increases its tribotechnical characteristics during dry friction, reduces its corrosion and tribocorrosion resistance by 2-2.5 times. The modification of the Nickel matrix of BH20 composite by chromium carbides (1% Cr3C2) decreases the corrosion rate in 3% NaCl solution and the corrosion-mechanical wear by 10-12%. It is shown that the corrosion resistance of this alloy increases with increasing pH of the solution from 2.5 to 9.9 , and the tribocorrosion resistance increases 2-3 times.
It is shown that the chromates, which are effective corrosion inhibitors, accelerate tribocorrosion of the aluminum alloy by ~ 40% due to the formation of conversion films. Instead, zinc phosphates increase the corrosion and wear resistance of D16T aluminum alloy by ~30% due to the formation of plastic secondary structures. The rate of formation these structures depends on the mechanical and electrochemical factors.
It was found that the addition of silver and phosphate nanoparticles to aqueous environments and lubricants increases the tribological and tribocorrosion behavior in friction pairs of steel 20 – steel ШХ15 by ~ 35%. The composition of lubricants with the addition of nanoparticles is proposed, which is used in the nodes of drill bits and reduce their wear.
The results of the work have been implemented in the enterprises of Ukraine, in particular at PAE "Konotop Rebar Plant", LLC "Universal Drilling Equipment" and the state research and production enterprise "Alcon-Tverdosplav".
