Wear Mechanism and Electrochemical Properties of Different Interlayers on DLC Film Deposited by PECVD Technique

This research is an attempt to coat diamond-like carbon (DLC) thin films on AISI 420 stainless steel substrate by plasma-enhanced chemical vapor deposition (PECVD). The plasma nitriding process and the creation of a zirconium nitride (ZrN) layer were used to increase the adhesion of the coating to the substrate. Microstructural studies using field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM) showed that all the coatings contained no porosity and were completely dense so that the mean surface roughness (Ra) of the ZrN-DLC coating was 3.02 nm. The corrosion polarization test showed that applying the coatings improved the corrosion resistance i.e., the corrosion current density of the ZrN-DLC sample was 3.6 × 10^–8 A/cm², which was at least 1000 times better than that of the substrate. The samples contained DLC exhibited improved wear behavior than other samples. The plasma-nitrided DLC sample was the best in the wear test, so much so that the DLC in this sample was able to prevent the transfer to the abrasive mechanism.