The Effects of Ti/Ni Doping on the Friction and Wear Properties of DLC Coatings

Diamond-like carbon (DLC) coatings doped with Ti and Ni elements were deposited on 316 L stainless steel substrate using magnetron sputtering technology. The morphology, microstructures, and performances of the coatings were detected using scanning electron microscopy, a Raman spectrometer, nanoindenter, scratch tester, and a tribological machine. The effects of element doping on the microstructures, friction and wear properties of DLC coatings were analyzed. The results revealed that Ti/Ni doping ensures the uniform cover and tight fit of DLC coatings on the substrate. Additionally, Ni-doped DLC coatings have a much smoother surface and denser texture with higher bonding strength and enhanced hardness (7.5 GPa) though Ti doping also can improve the bond strength to some extent. The presence of Ni both in the 316 L substrate and in Ni-doped DLC coatings improves interface matching, decreases structural differences, and increases bonding strength. Moreover, the presence of Ni effectively inhibits oxidation and corrosion in friction interfaces, stabilizes the friction coefficient, and enhances wear resistance. Therefore, based on this study, it was concluded that reasonable matching between the dopant elements and the substrates can effectively improve the performance of DLC coatings.