2015 Volume 55 Issue 12 Pages 2631-2638
In this study, diamond-like carbon (DLC) films are coated by bipolar-pulsed PECVD onto oxynitriding-treated JIS SKD11 steel. In order to evaluate the properties of the DLC/oxynitriding films on SKD11 steel, Raman spectroscopy analysis, wear tests, adhesion tests, hardness tests and corrosion resistance inspections are performed. The experimental results show that the DLC/oxynitride duplex layers possess ideal wear and corrosion resistance when DLC films are deposited by unbalanced bipolar-pulsed voltage, with a coating time of 90 min and duty cycles maintained at 15%. The highest surface hardness (Hv0.025 2830.7) and lowest wear volume loss (when the load of 2 N and sliding speed of 0.05 m·s−1 is 4.07 × 10−3 mm3 and the load of 5 N and sliding speed of 0.25 m·s−1 is 5.83 × 10−3 mm3, respectively) are obtained. In addition, the optimal DLC/oxynitride films also possess the lowest corrosion current (Icorr = 2.66 × 10−6 A·cm−2) and highest polarization resistance (Rp = 1.57 × 104 Ω·cm2) in 3.5 wt% NaCl solutions.