| Abstrakt: |
The mechanism of self-organization on the contact surfaces of rubbing bodies of wear-resistant over finely dispersed coatings is investigated. Thanks to these coatings, in an air-water environment, the contact pair of steel 130Cr17-steel 20Cr13 goes into a stationary mode of working with minimal wear and a coefficient of friction. The study shows that wear-resistant over finely dispersed coatings consist of separate layers. These layers are the result of the layering of metal microprotrusions on the friction surface. These microprotrusions are formed during the breaking-in of friction units because of the local metal destruction and its transfer between bodies due to strong adhesive interaction between friction surfaces. Friction layers consist of a qualitatively new over fine-grained material that can contain up to 25% oxygen and carbon atoms, most of which do not form chemical compounds with the atoms of the initial metals. As established, under conditions of high-energy impulse impacts, the deformation of metal microvolumes layering on the friction surface occurs due to the collective forms of motion of crystal lattice defects. Therefore, the friction layers consist of over finely dispersed systems with spatially disoriented grains. Their boundaries are formed by branched dislocation clusters and have a spatially extended shape. It has been shown that in the case of a high intensity of impulse thermomechanical influences, when the collective forms of motion of crystal lattice defects cannot provide further rate deformation of metal microvolumes, there is a phase transition of over finely dispersed systems saturated with oxygen and carbon into a quasi-liquid structurally unstable state. This is evidenced by the appearance of an amorphous nanostructured material in the final part of some layers of friction. The nanostructured material has a clear boundary with ultradispersed metal, contains the maximum quantity of oxygen atoms and is characterized by high hardness and elasticity. [ABSTRACT FROM AUTHOR] |
