Tribological properties of duplex Cr-Si-N coatings on SS410 steel

Hardness and other mechanical properties of CrN can be enhanced by adding small amounts of Si, an effect that can possibly be attributed to solid solution hardening. In the present work, tribological properties of the Cr-Si-N coatings on SS410 steel substrates were studied. These samples were prepared by a duplex treatment consisting of surface nitriding and deposition of a Cr bond-coat, which also provides the highest adhesion. The influence of silicon concentration on the tribological properties was determined by ball-on-disc and ball-on-flat tests, while the wear mechanism against an alumina ball was assessed by analyzing the wear track and the wear debris using SEM, EDX and Raman spectroscopy. It was found that the coating containing 2.3 at.% of Si, corresponding to the solubility limit, exhibits the best mechanical and tribological performance: the wear rate of the SS410 substrate has been reduced by a factor of 500, corresponding to a hardness and wear coefficient of 25 GPa and 2-4 × 10− 7 mm3/N m, respectively.