The effect of substrate and DLC morphology on the tribological properties coating

We studied the effect of the initial substrate surface roughness and as grown DLC microrelief on the tribological properties of coating. The diamond-like films were prepared by pulse are sputtering of graphite onto R6M5 and 20Cr13 tool steel substrates. Special attention was paid to production of the DLC having increased the friction coefficients necessary for such device as printing machine valves and chuck's jaws. The tribological properties of the deposited coatings were studied under conditions of dry sliding friction and under the action of an abrasive-particle jet. ft was shown using both testing methods that the substrate surface roughness (R) is the decisive parameter for the wear resistance of the DLC to external loads. The wear resistance of coating is increased several-fold at some optimal R-value as compared to the smoother surface. The optimal R-value depends on the coating thickness, h. The optimal R/h value should not deviate largely from the ratio R/h similar to 0.2-0.3. (C) 2000 Elsevier Science S.A. All rights reserved.