Investigation of the structure and phase composition of the microdroplets formed during the deposition of PVD coatings

The paper deals with the features of the structure and phase composition typical for the microdroplets of various elemental composition, including Ti, Zr, Cr, and AlN, and the effect of microdroplets on the structure of nanolayer coatings of TiN-(Ti,Al)N, TiN-(Ti,Mo,Al)N, ZrN-(Zr,Mo,Al)N, and CrN-(Cr,Mo,Al)N. The studies were carried out using the methods of transmission electron microscopy, X-ray spectroscopy and scanning transmission electron microscopy. The experiments revealed the specific features of the deformation of the nanolayer structure of the coating under the impact of microdroplets hitting the coating surface. The study also determined the phases formed in the microdroplets of various compositions. The diffusion processes have been investigated, during which the metals, contained in the coating (in particular, molybdenum (Mo)), dissolve in the surface layers of the core of the main microdroplet element. According to the study, microdroplets can be formed both by pure metals and by their nitrides. The paper considers the possibility of a positive effect of a microdroplet on the cutting process due to the formation of an intermediate layer of a solid lubricant between the coating and the material being machined. •The influence of microdroplets on the structure of a nanolayer coating•The possible function of a microdroplet as a solid lubricant during the cutting process•The formation of multicomponent phases in a microdroplet