Enhancing interfacial strength of DLC films on plasma-nitrided stainless steel

An interfacial toughness of diamond-like carbon (DLC) films onto the stainless steel substrates is of progressive importance due to the countless tribological advantages of DLC in recent industries. The purpose of this article is to enhance the adhesion strength of DLC amorphous film on martensite stainless steel by introducing two different layers. A combination of nitrogen supersaturation layer and SiC x :H interlayer film were utilized to achieve this purpose. The nanograined, hard nitrogen-supersaturated layer, acted as a transition zone, having more homogenous load-bearing capacity than all coatings onto the non-nitrided substrate. Moreover, SiC x :H interlayer attains Si N and C N bonds between the nitrogen-supersaturated layer and SiC x :H interlayer. These bonds have a direct influence in increasing the number of stable sp 3 hybridization bonds between these two layers which ultimately further improve the interfacial strength. • Nitrogen supersaturation layer and SiCx:H interlayer were employed to improve the adhesion of the top a-C:H film. • Different techniques such as Rockwell C indentation, scratch, and XPS were used to understand the reasons for improved adhesion. • The adhesion of a-C:H films on stainless steel is doubled with the combination of SiCx:H and nitrogen supersaturation layer. • The nanograined hard nitrogen-supersaturated layer is demonstrated to significantly increase the interfacial strength. • Forming Si N and C N bonds in the interlayer enhances interfacial strength.