On the understanding of the silicon-containing adhesion interlayer in DLC deposited on steel

DLC is a promising material to be used in technological issues. However, its poor adhesion on steels keeps away from a wide range of applications. Thus, an understanding of the physicochemical structure of the DLC/interlayer/steel system in correlation with a mechanical model is mandatory in order to explain the tribological behavior as a whole. In this work, DLC was deposited on AISI 4140 low-alloy steel through a silicon-containing interlayer. Two different delamination critical loads were determined and they were associated with different failure mechanisms that took place at the outermost and at the innermost interfaces of the silicon-containing interlayer. The Hertz contact theory was used to evaluate the shear stress distribution at the applied normal loads during the scratch tests.