Study of Tribological and Mechanical Characteristics of Wear-Resistant Coatings Taking into Account Their Elastoplastic Properties

The influence of the elastic-plastic properties of the coating-substrate system on the mechanical and tribological properties of coatings is investigated in the present work. The mechanical and tribological properties of the coatings were obtained by tribological testing and indentation. A screening experiment for vacuum ion plasma coatings of nitride systems of TiAlN and CrAlSiN deposited on steel substrates (38X2MYA, 12X2H4A) was performed. The mechanical properties of the coatings were determined using the NanoTest 600 continuous indentation method. The microstructure of the coatings and their surface topography were studied using a high-resolution ZEISS CrossBeam 340 scanning electron microscope (SEM). Tribological tests of the nitride coatings were performed on a TRB friction machine (Anton Paar Tritec) according to the methods of DIN 50 324 and ASTM G99. In addition, the indentation process of nitride coatings was studied based on the solution of the quasi-static contact problem when introducing a rigid indenter into an elastoplastic two-layer half-space. The mechanical characteristics H/E and H3/E2 of the considered coatings and the conditions of adhesion failure between the layers have been determined. Theoretical studies are compared with the results of laboratory experiments. It is shown that when setting up laboratory experiments on indentation and tribological tests of coatings it is necessary to control not only the permissible depth of penetration of the indenter, but also the ratios of elastic-plastic properties of the coating and the substrate. It has been found that the service life of tribo-conjugate elements with coatings of a certain thickness can be increased by combining the elastic-plastic properties of the layered medium adapted to the given loading modes. This will prevent the localization of tensile and compressive stresses and delamination and cracking at the interface of two materials.