Tribological and mechanical properties of multilayered TiVN/TiSiN coatings synthesized by cathodic arc evaporation

The flexibility of the physical vapor deposition (PVD) method in obtaining coatings with a delicate control at a nanometric level provides superior properties. Among these coatings, transition metal nitride coatings based on Ti, Si, Al and V, such as TiAlN, TiSiN and TiVN, have been attracting great interest for industrial applications as protective coating materials due to their high hardness, wear resistance and tribological performance. In this study, TiVN, TiSiN and multilayered TiVN/TiSiN coatings were deposited onto tungsten carbide tools using cathodic-arc evaporation (CAE) system. During the coating process of TiVN/TiSiN, TiN was deposited as an interlayer to enhance adhesion strength between the coatings and substrates. The main objective of the present work is to investigate the effect of TiVN on the microstructure, mechanical properties and tribological performance of the deposited TiVN/TiSiN coatings by regulating the bias voltage during the coating process. The multilayered TiVN/TiSiN coatings exhibited higher hardness of 35-37 GPa, indicating higher resistance against plastic deformation compared to TiVN and TiSiN. The result of ball-on-disc wear tests and end milling tests of 7000 series Al alloys showed that the lowest wear rate and the longest tool life were obtained for the multilayered TiVN/TiSiN coating deposited at high bias voltage of 180 V, which was significantly better than that of the monolayered TiSiN.