Effects of Hf addition on the structure, mechanical and tribological properties of CrN film

Abstract Alloying elements in binary nitride is considered as a promising method to design hard and tough films. Hf atoms are proposed to be incorporated in CrN nitrid films to form ternary nitrides, which may possess the improved mechanical and tribological properties. In this study, Cr1-xHfxN [x = Hf/(Cr + Hf)] films were sputtering deposited by incorporating Hf into CrN film in an mixed atmosphere of Ar and N2. The influences of Hf addition on the microstructure, mechanical and tribological properties of Cr1-xHfxN films were investigated. The results show that the hardness and fracture toughness of CrN film is significantly improved due to solid solution strengthening by incorporating Hf atoms. Thanks to the improved hardness and toughness, the wear resistance of CrN film is enhanced. A high H/E and H3/E2 values, which are regarded as the reflection of toughness of hard films, are obtained from Cr0.69Hf0.31N film with higher hardness (30.49 GPa). The lowest wear rate of about 1.03 × 10−6 mm3/Nm is also presented for Cr0.69Hf0.31N film, which corresponds to higher H/E(~0.125) and H3/E2(~0.481 GPa).