Structure and properties of Zr/ZrCN coatings deposited by cathodic arc method

Zr/ZrCN multilayers, with bilayer periods ranging from 4.4 to 70 nm, were deposited on C45 and M2 steels and Si substrates by the cathodic arc technique, in a CH4 + N2 atmosphere. The elemental and phase composition, modulation periodicity, texture, surface morphology, residual stress, hardness, adhesion, friction and wear behavior were investigated as a function of bilayer period and C/N ratio using AES, RBS, XRR, XRD and AFM techniques, surface profilometry, Vickers microhardness and scratch adhesion measurements, and tribological tests. Two types of Zr/ZrCN multilayers, with high and low C/(C + N) ratios (0.7 and 0.2, respectively) in the ZrCN sub-layer composition, have been prepared. The investigations indicated that the microchemical, microstructural, mechanical and tribological characteristics of the multilayered coatings depended on C/N ratio and bilayer period. For the optimum structure parameters (bilayer periods in the range 6–13 nm), the tribological performance of the multilayers was found to be superior to that of the ZrCN monolayers.