An evaluation of the tribological characteristics of DLC films grown on Inconel Alloy 718 using the Active Screen Plasma technique in a Pulsed-DC PECVD system

• The novel ASP technology has gradually been adopted by industry due to its advantages in conventional direct current (DC) plasma treatment processes like carburising, nitriding, and carbonitriding.
• However, the expansion of this technology has been limited by the lack information and understanding of the mechanisms involved in the DLC film growth process.
• The Active Screen Plasma technique (ASP) is being applied in plasma surface engineering to provide uniform material properties and to obtain films under low temperature for low lower power.

Tribology properties of Diamond-Like Carbon (DLC) films are important for the petroleum industry because of their low friction coefficient, hardness, good wear resistance, and corrosion. In this study, the DLC films were deposited on Inconel Alloy 718, using the Active Screen Plasma (ASP) technique in a Pulsed DC-PECVD system. Plasma carbonitriding was used as a pretreatment followed by the deposition of an amorphous silicon interlayer to increase adhesion and improve the tribological performance of the DLC coatings; everything described above was performed in a single continuous process of deposition. This paper analyzes the tribological behavior of the DLC films. The layers were observed with SEM and Raman spectroscopy. The tribological behavior was analyzed by linearly reciprocating wear tests at room temperature and at 150 °C. Adhesion was tested according to the VDI3198 standard based on a Rockwell C indentation and scratch test. The coatings registered a hardness of 20 GPa, showing better wear resistance and elevated adhesion, than the uncoated substrate.