A Chemical, Mechanical, and Tribological Analysis of DLC Coatings Deposited by Magnetron Sputtering

Abstract

Diamond-like carbon is one of the most studied and used solid lubricants on the market. Despite this large use and its outstanding mechanical and tribological properties, there are still some unclear aspects related to its self-lubricant properties, and some drawbacks in the deposition methods. We deposited “soft” DLC films on Si(100), iron, and stainless steel substrates by PVD magnetron sputtering technique with a Cr/CrN adhesive interlayer. The DLC films were characterized from a chemical, mechanical, and tribological point of view. Our aim was to connect the coating chemical and mechanical characteristics to the different conditions used for the deposition, such as discharge power and substrate–target distance. We found a stronger sp3 dependence on the discharge power for DLC deposited closer to the target. The tribological results did not depend on the chosen substrate–target distance, but rather on the hardness of the substrate. This could be ascribed to the better mechanical coupling of soft DLC films on harder substrates.

Impact of Plasma Pre-Treatment on the Tribological Properties of DLC Coatings on PDMS Substrates

“…Carbon coatings are a very well investigated material used to improve multiple properties of the surface layer. They can be used to increase hardness [ 1 , 2 , 3 ], improve wear resistance, reduce the coefficient of friction [ 1 , 2 , 3 , 4 , 5 ] and enhance the biocompatibility of the modified surface [ 6 , 7 ] or its resistance to colonisation by micro-organisms [ 7 , 8 ]. Due to their advantages, diamond-like carbon (DLC) coatings are tested in a wide range of applications in very different areas: biomedicine [ 5 , 6 , 7 , 8 , 9 ], machining [ 10 , 11 ], electronics [ 12 , 13 ] and electrochemistry [ 14 , 15 ].…”

Diamond-Like Carbon (DLC) Coatings: Classification, Properties, and Applications

“…In another study, soft DLC films were deposited on Si (100), iron, and chrome steel substrates with a Cr adhesive interlayer using PVD magnetron sputtering technology [85]. The major output was to connect the coating chemical and mechanical behaviors to the various deposition parameters, such as discharge power and substrate-target distance.…”

Electrical Conduction Properties of Hydrogenated Amorphous Carbon Films with Different Structures

“…The most popular process to synthesize a -C:H films is plasma-enhanced chemical vapor deposition (PECVD) [ 2 ]. The mechanical and tribological properties of a -C:H films depend on their atomic structure [ 3 ]. These films, and particularly what is called diamond-like carbon (DLC) films, have outstanding mechanical properties, such as high hardness, low coefficients of friction and excellent corrosion and wear resistance.…”

“…These films, and particularly what is called diamond-like carbon (DLC) films, have outstanding mechanical properties, such as high hardness, low coefficients of friction and excellent corrosion and wear resistance. Fiaschi et al reported that the hardness of DLC films depends on their sp 3 content and that the hardness affects tribological properties [ 3 ]. Many researchers have mentioned that the friction coefficient and specific rate of the films were affected by their hydrogen content [ 4 , 5 , 6 ].…”