Wear resistance of a high-nitrogen austenitic stainless steel coated with nitrogenated amorphous carbon films

In this paper, the dependence of wear resistance on grain size of nitrogen-alloyed austenitic stainless steel is investigated and compared to measurements for the same samples coated with nitrogenated amorphous carbon [a-C:H(N)] film, deposited by means of plasma-enhanced chemical vapour deposition. To this aim, ball-on-disk (BoD) tests were performed to investigate the wear stability of coated and uncoated substrates. Long-time test results on the uncoated material show that no improvement in the low-friction performance (LFP) duration was found with decreasing grain size of the substrate. On the other hand, an improvement in the low-friction performance duration with substrate microstructure refinement was found in the case of nitrogen-doped overcoats. An effect of the film structure on the LFP duration was also detected in the case of the finest-grained samples, indicating a synergic effect between the ultrafine grain structure and the nitrogen-doped carbon coating. (C) 2002 Elsevier Science B.V. All rights reserved.