Increased Operating Properties of Cutting Ceramics by Application of Nanostructured Multilayer Wear-Resistant Coating

This paper presents the results of the development of nano-scale multi-layered composite coatings for improving the contact performance of ceramic cutting tools. These nano-coatings help reducing brittle fracture of cutting edges and ensure a balanced wear of tool contact areas during dry high-speed machining of hardened steels. A filtered cathodic vacuum arc deposition process was used to generate the nano-scale multi-layered composite coatings (NMCC) with improved physical and mechanical properties and adhesion strength to ceramic substrate. In this work, thermodynamic criteria were used to evaluate the selected composition of NMCC, and the crystal-chemical, physical, mechanical and cutting properties and wear mechanisms were studied. Ti-(TiAl)N-(ZrNbTiAl)N coating was deposited on Al2O3, Al2O3-TiC and Si3N4 ceramic substrates. Test results showed that the wear mechanism of the coated tool was predominantly due to adhesive-fatigue processes. The development of wear was observed to be centered on the rake and flank faces of the tool without brittle chipping. The results of high-speed longitudinal turning of hardened steel X153CrMoV12 showed an increase in tool life by a factor of 1.5 against the uncoated tools and a factor of 1.3 compared with standard PVD coating Ti-(TiAl)N.