2018 年 58 巻 8 号 p. 1510-1518
In the present research, DLC films are produced by asymmetric bipolar pulsed plasma enhanced CVD after preparing oxynitride-treated PM30 steel. The experimental parameters include various CH4 gas flows (3, 7, 11, 15 and 19 sccm) with asymmetric bipolar pulsed voltages (−15+10%) and a deposition time of 90 min, respectively. In order to evaluate the properties of the DLC films for oxynitride-treated PM30 steel, Raman spectroscopy analysis, adhesion tests, nano-indentation, wear tests, and corrosion resistance inspections were performed. The experimental results reveal that the DLC/oxynitride duplex coating layers have better properties when the DLC films are treated with an appropriate CH4 gas flow (15 sccm). Meanwhile, the coatings possess the highest hardness and elastic modulus (5.91 and 89.87 GPa, respectively), the lowest wear loss volume (for axial loads of 2 and 5 N of 3.82 × 10−3 and 5.49 × 10−3 mm3, respectively), the lowest corrosion current (1.43 × 10−4 A·cm−2), and the highest polarization resistance (5.32 × 102 Ω·cm2) after a 3.5 mass% NaCl corrosion test. This study also confirms that the wear and corrosion resistance of DLC/oxynitride duplex-treated PM30 steel can be effectively improved via asymmetric bipolar pulsed plasma enhanced CVD.
