Maksakova O. Structure and physical-mechanical properties of composite coatings based on ZrN/CrN

The thesis is devoted to the establishment of the relation between structure, chemical composition and stress state with thermodynamic and mechanical properties of composite coatings based on ZrN/CrN. The SAED studies of experimental coatings indicate the formation of a two-phase state, which corresponds to fcc-ZrN and doublet hcp-Cr2N + fcc-CrN. It has been established that the main defects in the crystal structure of the coatings are complete and partial dislocations and packing faults. The study of the effect of high-temperature annealing on the structural phase state of ZrN/CrN coatings was carried out for the first time, and it was shown that, depending on the bias potential, two types of thermal reactions were possible in composites: exothermic and endothermic. The studied coatings in the initial state were under tension and compression stresses, the value of which depends on the nitrogen concentration in the coating and the average grain size. Multilayer coatings ZrN/CrN are characterized by high mechanical properties, in particular, the nanohardness up to 26.8 GPa, the modulus of elasticity up to 315 GPa, elastic recovery up to 0.31and the viscosity-plastic index up to 0.085. The introduction of metal layers (Cr/Zr) increases the mechanical properties of the coatings: hardness up to 34 GPa, elastic modulus up to 330 GPa.