Influence of Bilayer Period on the Characteristics of Nanometre-Scale ZrN/TiAlN Multilayers

In the last decade, considerable research effort was directed to the deposition of multilayer films with layer thicknesses in the nanometer range (superlattice coatings), in order to increase the performance of various cutting tools and machine parts. The goal of the present work was to investigate the main microstructural, mechanical and wear resistance characteristics of a superlattice coating, consisting of alternate multilayer ZrN/TiAlN films, with various bilayer periods (5÷20 nm). The coatings were deposited by the cathodic arc method on Si, plain carbon steel and high speed steel substrates to be used as wear resistance surfaces. The multilayer structures were prepared by using shutters placed in front of each cathode (Zr and Ti + Al). The characteristics of multilayer structures (elemental and phase composition, texture, Vickers microhardness, thickness, adhesion, and wear resistance) were determined by using various techniques (AES, XPS, XRD, microhardness measurements, scratch, and tribological tests). A comparison with the properties of ZrN and TiAlN single-layer coatings was carried out.