Deposition and characterization of (Nb,Cr)N thin films by unbalanced magnetron sputtering

Several (Nb,Cr)N thin films were deposited by an unbalanced magnetron sputtering system. The coating properties as a function of Nb/Cr ratio were studied using glow discharge optical spectrometer (GDOS), SEM, XRD, AFM and nano-indentation measurement. The tribological properties were then carried out using a ball-on-disk setup with alumina balls. The wear results show that coatings which are Cr-rich yield much lower values of friction coefficient and low wear rates than coatings which are Nb-rich in compositions for the same tested distance and speed. The effects of Nb/Cr ratios on the coatings surface texture, structure morphology, hardness, and crystal structure are also discussed.