Microstructure, Interface, and Properties of Multilayered CrN/Cr2O3 Coatings Prepared by Arc Ion Plating

There has been much interest in developing multilayered or nanolayered physical vapor deposition (PVD) coatings identified as a group of promising protective coatings for their excellent mechanical properties and corrosion resistance. In this study, the multilayered CrN/Cr2O3 coatings with different bilayer periods (Λ) were synthesized on the polished high speed steel substrates from a Cr target with the alternative atmosphere of pure nitrogen and pure oxygen by arc ion plating (AIP) technique. The results revealed that the microstructure, morphologies and properties of the multilayered coatings were strongly influenced by the bilayer period (Λ). There were two kinds of interfaces in the multilayered CrN/Cr2O3 coatings: the sharp ones and the blurry ones. With reducing the value of Λ, the macro-particles densities decreased gradually, whereas the coating microhardness, adhesive strength and wear resistance first increased, and then decreased slightly or remained stable as the bilayer period Λ < 590 nm. The multilayered CrN/Cr2O3 coating with the bilayer period Λ of 590 nm possessed the best comprehensive properties, namely the highest microhardness, the strongest adhesion, and the lowest wear rate.