Deposition behaviours of CrN films on the edge area by cathodic arc plasma deposition process

The deposition behaviours of CrN films were evaluated on the various geometrical angles of H13 steel in the cathodic are plasma deposition process. Specimens were prepared with edge angles of 30 degrees, 60 degrees and 90 degrees and deposited with CrN at various DC bias voltages of 0-400 V in continuous or interrupted modes. The film surface morphology and growth rate were significantly changed with the edge angle. The deposition rate was enhanced with an increase in edge sharpness. The noted feature of the CrN coating on the sharp edge region is the remarkable surface roughening due to accelerated accumulation of deposited vapour molecules at many localized spots during continuous DC biased coating. The atomic ratio of Cr to nitrogen was also varied from the edge tip to the bottom zone for angled specimens. Interrupted DC biasing at 100 V during deposition could effectively reduce the particle accumulation, thereby providing the confirmed smooth coating. (C) 1998 Elsevier Science S.A. All rights reserved.