Hard coating performance enhancement by using [Ti/TiN]n, [Zr/ZrN]n and [TiN/ZrN]n multilayer system

In order to increase the performance of hard coatings for industrial application, Ti/TiN, Zr/ZrN and TiN/ZrN multilayers were deposited onto Si(1 0 0) and AISI 5160 steel substrates via r.f. (13.56 MHz) multi-target magnetron sputtering technique. The crystallography structures of Ti/TiN, Zr/ZrN and TiN/ZrN multilayers were evaluated via X-ray diffraction analysis (XRD). The composition, chemical-depth distribution and cross-sectional morphology of the films were characterized by EDX, SIMS, and SEM. The enhancement of mechanical properties and adherence strength behavior were determined via nanoindentation and scratch test, respectively. From these results, it was found that hardness and critical load of all multilayer films depends on the bilayer period (Λ) and bilayer number (n). Moreover, the TiN/ZrN multilayer films exhibit the highest hardness (30 ± 1 GPa) and critical load (60 ± 1 N) in relation to Ti/TiN and Zr/ZrN multilayers. The different mechanical performances and mechanisms in the multilayers group were observed and discussed in this paper, suggesting the possibility to use AISI 5160 steel coated with multilayers as cutting tools.