Characteristics and performance of Cr2O3/CrN double-layered coatings deposited by cathodic arc plasma deposition

In this study, Cr2O3/CrN double-layered coatings synthesized by the cathodic arc plasma deposition were evaluated for potential application in injection molding dies. The double-layered coatings were designed with CrN of constant thickness as an interlayer and Cr2O3 of various thickness as a surface layer. Cr2O3 coatings of different thickness were deposited at varied times under the mixture of N2 and O2 at a constant flow rate. Well-adherent Cr2O3/CrN double-layered coatings were identified using scratch test and Rockwell C indention test. Characteristics of Cr2O3/CrN double-layered coatings were investigated by using XRD, XPS, SEM, tribological tests, and water contact angle measurement. The XRD analysis showed an increasing peak intensity of the Cr2O3 phase as the thickness of the top layer increased. The double-layered coatings exhibited an enhanced hardness of 32 GPa comparable to that of CrN (20 GPa). The tribological property of Cr2O3/CrN double-layered coatings also compared favorably with that of CrN film. The water contact angle measurement revealed that Cr2O3/CrN double-layered coatings were 40% higher than CrN film.