Reshetnyak O. Structure and properties of strengthening nanocrystalline coatings based on metal nitrides deposited from filtered vacuum-arc plasma

The dissertation is devoted to solving of the scientific problem of revealing the general laws and mechanisms of formation of the structure and properties of strengthening nanocrystalline coatings on the base of metal nitrides deposited from filtered vacuum-arc plasma. According to the results of studies on composition, structure, mechanical characteristics, wear resistance, thermal stability of two- and multi-element coatings based on nitrides of Ti, Cr, Al optimum conditions for formation of coatings with a complex of high protective properties were determined. The advantages of the coatings deposition using the magnetoelectric plasma filter of rectilinear type are shown. It was found that the application of the pulse potential of the displacement of a kilohertz frequency with amplitude of 1-2 kV and a pulse fill factor of 10-15% allows forming in a coating of different composition a homogeneous dense nanocrystalline structure with an axial texture [110] or [100], a small level of stress and defects. It is determined that such a structure provides high stability of coatings to different types of wear. The peculiarities of synthesis and properties of coatings of various composition are analyzed. In theoretical consideration of the physical mechanisms of coating formation, a thermodynamic approach based on the occurrence of nonlocal thermoelastic peaks under the action of ion bombardment has been applied. The formation of the structure, stress and texture in the coatings are considered together, as a result of the relaxation processes in the heat peak, aimed at minimizing the free energy of the system.