On the mechanisms of the formation of nanocrystalline Cr-N and V-N coatings upon ion-beam-assisted deposition

The paper generalizes the results of investigations performed at the Kharkov Institute of Physics and Technology, National Scientific Center, aimed at the development and analysis of nanocrystalline Cr-N and V-N coatings produced by the method of ion-beam-assisted deposition (IBAD method). The effect of temperature of the process and the ratio between its ionic and atomic components (N+/Cr, V) on the resistivity of the coatings has been studied. It has been found that the ion-assisted irradiation leads to the formation of nanocrystalline nitride structures, whose phase composition depends not only on the concentration of nitrogen implanted by the ion beam, but also on the amount of the physical adsorption of nitrogen, including its adsorption from the residual atmosphere. It has been shown that the IBAD method can be used for both production of dense nanocrystalline composites and creation of nanoporous structures. It has been found that the grain size, the internal porosity, and the electrophysical characteristics of the coatings are intimately connected with the Gibbs energy of the nitride phases. The mechanisms responsible for the formation of such coatings have been discussed in terms of the thermodynamics of the nitride-formation process.