Adhesion Enhancement on a Duplex DLC HiPIMS Positive Pulse Coating Performed by Active Screen Plasma Nitriding Pretreatment on 316L Stainless Steel Substrate

Abstract

Diamond-like carbon (DLC) coatings have been the object of research interest due to properties such as excellent wear resistance, low coefficient of friction, high hardness, high elastic modulus, and biocompatibility. Despite this, DLC has poor adhesion properties, which makes it challenging to use in industrial applications. The application of DLC using the high-power pulse magnetron sputtering (HiPIMS) technique with positive pulses has been studied. Seeking greater DLC coating adherence, the application of a nitriding pretreatment prior to the DLC coating has been studied to improve its adhesion to AISI316L stainless steel soft metal substrates, employing active screen plasma nitriding (ASPN). The influence of the different pretreatment temperatures to reach the maximum levels of adhesion has been analyzed. Scratch methods have been employed to assess adhesion. The elemental composition, morphology, and roughness of the samples have been studied, as well as the behavior of resistance to wear and friction. The results show an improvement in DCL adhesion. Critical loads (LC3) increase at higher pretreatment temperatures, from 48 N for the DLC to 82 N for the ASPN + DLC. Pretreatment has also been shown to be effective in maintaining excellent dry wear resistance properties and a low coefficient of friction.