Structure and Corrosion Resistance of Vacuum-Arc Multi-period CrN/Cu Coatings

The influence of deposition conditions (pressure, bias potential, layer thickness) on the structure and corrosion resistance of vacuum-arc multi-period CrN/Cu coatings is studied. For research, we used the methods of precision XRD, scanning electron microscopy with energy dispersive microanalysis, impedance spectroscopy, and potentiodynamic polarization tests to detect corrosion resistance in a solution of 0.9% NaCl. According to structural studies, phases with an fcc crystal lattice are formed in the layers: Cu and CrN mononitride. In CrN layers obtained at the highest bias potential of -200 V, a change in the lattice period associated with the action of compression stresses was revealed. Tests for corrosion resistance showed that for all the samples studied, the corrosion process has a predominantly anodic reaction. The most corrosion-resistant coatings are those obtained at a pressure of 5.10(-4) Torr and the greatest bias potential of -200 V in constant rotation mode. The feature of such coatings is the smallest thickness of copper and CrN layers (about 8 nm), the presence of compression stresses (which enhances adhesion between the layers), and the absence of a pronounced texture (the paths of easy diffusion are minimized).