EFFECT OF N2 PARTIAL PRESSURE ON THE GROWTH OF CHROMIUM NITRIDE COATINGS

Abstract

Chromium nitride films has been prepared by reactive magnetron sputtering using a mixture of Ar and N2 gas. Keeping constant the total pressure during the film deposition the ratio of N2 to Ar has been varied from 0.3 to 5.0 to promote the growth of CrN films with different microstructure. The structural chemical characterization of grown films were performed by means of x-ray diffraction and scanning electron microscopy, auger electron spectroscopy and x-ray photoemission spectroscopy. Even if no clear correlation between material hardness and coating microstructure was observed with nanoindentation, the tribological characterization of the films, evidenced a strong dependence of the wear rate of the material by the process conditions. In particular we observed an improved wear resistance for coatings with a compressive residual stress.