Theoretical evaluation of the performance of greases with additives

Abstract

The formation of protective films under the action of additives on friction surfaces is a rather complicated process. In the first approximation, when the materials of the additive present in the lubricant interact with the substrate material, physicochemical processes should occur, as a result of which the near-surface structure of the metal changes, etc. The stability of a structured lubrication system depends on the strength of the structural framework, the forces of interaction between its individual particles, the dispersion medium at the interface, and the number of particle contacts per unit volume. The efficiency of the lubrication with additives from graphite and graphene components is considered. It was found that if we know the binding energy of 1 mole of the film and its thickness, it is possible to determine the separation pressure. As a result of a theoretical analysis of the processes occurring during the interaction of graphene particles with the surface of the substrate or metal, the dependence of the multiplier function on the number of layers in the film was established. An equation is obtained that characterizes the total area of separation of film fragments over the entire surface of the part, taking into account the pressure in the nodes and mechanisms and the stochastic nature of this phenomenon. It has been determined that the functioning of a new assembly or mechanism, pressure fluctuations are minimal due to minimal wear and optimal part tolerances. In the interaction of metal - metal additives, the electrons of the metal atoms are able to form an electron cloud in the crystal lattice, partially extending beyond the lattice. This can lead to the appearance of a dipole moment, the negatively charged pole of which is outside the metal lattice, and the positively charged pole is inside it. Metal nanoparticles that make up additives to lubricants, in contrast to graphenes, are nanosized 3D objects with a full-fledged crystal lattice, and therefore have higher dipole moments, which reduces the adhesive properties of the film, but in general does not contradict the known theories of their formation at certain conditions.