The effect of Cr/Zr chemical composition ratios on the mechanical properties of CrN/ZrN multilayered coatings deposited by cathodic arc deposition system

CrN/ZrN multilayer coatings with various Cr/Zr chemical compositions ratio were fabricated by a cathode arc deposition system. The Cr/Zr atomic ratios of the CrN/ZrN multilayer coatings were controlled, ranging from 1 to 2.5. The chemical composition of CrN/ZrN multilayer thin films was determined by a field emission electron probe microanalyzer (FE-EPMA). The phase composition of multilayer coatings was analyzed by a glancing angle X-ray diffractometer. Microstructures of the thin films were examined by field emission scanning electron microscopy (FE-SEM). Nanoindentation, the Daimler−Benz Rockwell-C (HRC-DB) adhesion, microhardness, pin-on-disc wear tests and scratch tests were used to evaluate the hardness, adhesion, toughness and tribological properties of the thin films, respectively. It was found that the hardness and tribological properties were strongly influenced by the Cr/Zr chemical composition ratios of the CrN/ZrN multilayer coatings. Optimal mechanical properties and the maximum hardness of 28 GPa were achieved for the coating when the Cr/Zr atomic ratio was 2.1.