Fretting wear properties of CrN and Cr2N coatings

Fretting wear experiments were carried out on CrN and Cr2N coatings. The chromium nitrides were deposited on 50 CrMo 4 steel substrate by reactive magnetron sputtering. The deposition conditions were optimised in order to obtain good adhesion and stoechiometric films. Scanning electron microscopy analyses were performed on the films. Fretting wear characterisations were conducted by using ball-on-flat geometries. By comparison with results obtained on the substrate, it was shown that fretting properties of Cr2N and CrN coatings are improved when grease lubricant is used in the mechanical contact.