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.