Hasiy O. Scientific Principles of Increasing the Service Life of Forestry Equipment Elements by Applying Vacuum Ion-Plasma Coatings.

The dissertation deals with the issue of increasing the service life of the tool and technological equipment with vacuum ion-plasma coatings, operating in conditions of contact interaction with structural materials and the working medium. Structural transformations in the TiN coating have been revealed, which is manifested in the transformation of the face-centered lattice into a rhombohedral lattice and is accompanied by the occurrence of compression stresses in the plane (111), which is a prerequisite for increasing wear resistance and endurance limits. The stress state in the coatings was investigated depending on the structural, temperature and force factors. An integrated study of the tribotechnical characteristics of one- and two-layer nitrogen-containing, Ti-based coatings under conditions of dry friction, boundary friction, modeling of the cutting process in contact with wood and steels has been carried out. No correlation was found between the ratio of the ranges of variation of the friction force and hardness of hardwoods and softwoods during friction across the fibers and the causes of relative decrease in frictional resistance based on the structural features of hardwoods compared to softwoods were established. Integrated studies of the corrosion resistance of coatings based on Ti, Mo, Ni, Nb, Fe, Cr in the medium containing H2SO4, Н3РО4, НСl, НNO3, NaCl have been carried out. Recommended are coatings that have the best protective properties in all tested media. The durability of coatings under conditions of corrosion-mechanical and cavitation-erosion wear as well as corrosion-fatigue strength in the NaCl medium has been investigated. Reagents have been identified that most effectively dissolve fatty acids on the surface of parts intended for vacuum ion-plasma coatings.