Study of cracking mechanisms in multi-layered composite nano-structured coatings

The mechanisms of cracking in multi-layered composite nano-structured coatings deposited through the use of the technologies of filtered cathodicvacuum arc deposition(FCVAD) (coatingsZr-ZrN-(ZrCrAl)N, Cr-CrN-(TiCrAl)N, Zr-ZrN -(ZrNbTiAl))and lateral rotating cathodes (coating Ti-TiAlN-TiAlN) are explored herein.The formed coatings are characterised by parameters such as hardness, adhesion strength to a substrate, elemental composition, microstructure, and the kinetics and mechanisms of wear. The microstructural studies have revealed the typical mechanisms of cracking and their influence on the kinetics of wear of coated carbide tools. The study also included extensive certification tests of cutting properties of tools equipped with cutting inserts of carbides with the coatings under study in the longitudinal turning of steelC45 (HB 200). The results of the studies have shown that all the coatings selected for study significantly increase the lifetime of carbide tools; the lifetimes were increased by up to 3-4 times in comparison with an uncoated tool and by 1.5-2 times in comparison with a tool with a "reference" coating of TiN. The influence of ZrNon the cracking mechanisms of coatings and the kinetics of tool wear were also explored.