Optimising tribological properties of anti-wear AlCrN coatings deposited by the cathodic arc method

The Taguchi method was applied to achieve the optimum anti-wear performance of AlCrN hard coatings deposited by the cathodic arc evaporation technique. Four deposition processes parameters i.e. nitrogen pressure, arc current, bias voltage and substrate temperature with three levels were selected ∗ Institute for Sustainable Technologies – National Research Institute, Pulaskiego 6/10, 26-600 Radom, Poland. T R I B O L O G I A 6-2014 12 to estimate the influence of each factor on the coatings defects and their mechanical and tribological properties. Based on the statistical analyses, the optimum deposition conditions were determined to manufacture AlCrN coatings with the best tribological behaviour. The results demonstrate that, the nitrogen pressure, arc current and the bias voltage influence the volume wear of the coating to the greatest extent. The results of the study of the surface topography and the mechanical properties of the AlCrN coatings showed that, in order to obtain the greatest resistance to wear, the coating must be sufficiently smooth (with a low number of surface defects), hard and demonstrate a good adhesion to the substrate. The optimum deposition conditions of the AlCrN coatings with the greatest resistance to wear are as follows: the nitrogen pressure 2.6 Pa, arc current 50 A, negative bias voltage 150 V and substrate temperature 465°C.