On the adhesion of diamond‐like carbon coatings deposited by low‐pressure plasma on 316L stainless steel

Diamond‐like carbon (DLC) thin films constitute proven protective coatings due to their outstanding mechanical and tribological properties, combined with a relative chemical inertness and long‐term stability. These make them particularly attractive to protect metallic medical implants from corrosion and erosion. However, lack of adhesion between DLC and metallic surfaces is a recurrent problem due to poor interactions with the native oxide layer. An effective strategy to overcome these adhesion issues consists in building interfacial layers. In this context, in this work, the use of a plasma treatment to generate shallow metallic carbide layers was investigated, to promote DLC adhesion directly on the surface of 316L stainless steel (SS). The metallic carbides presence stabilizes and promotes DLC thin film deposition. The highest adhesion was obtained on samples carburized by methane during 20 min with a bias of −700 V. Furthermore, this led to interface amorphization. In conclusion, this study shows that plasma can provide new insights for overcoming the lack of adhesion of DLC thin films on SS metallic surfaces.