Properties of protective carbon films applied on stainless steels via magnetronic sputtering

Thin films of hard diamond-like carbon (DLC), containing amorphous carbon with disordered graphite ordering, which is striving to a tetrahedral diamond-like coordination, are interesting for material scientists due to their excellent mechanical and tribological properties. Dense nanostructured carbon films DLS containing tetrahedral 46.7 % of sp3-links with nanoparticles having average size 28 ± 8 nm, were applied on stainless steel SS 304 samples via the method of high-frequency magnetronic sputtering without adhesive substrate and with it; their microstructural parameters were examined. The results displayed that assessed dimensions of individual carbon nanoparticles were varied within the range 25–27 nm. Obtained films of diamond-like carbon are characterized by rather low surface roughness at the level 3.6 nm. It is an important practical property, because low roughness promotes decrease of friction and wear, what can be required in various technological applications. DLC films displayed hydrophilic behaviour with measured value of the contact angle 62 ± 2° and 55 ± 2° (for a film with adhesive titanium layer) in comparison with the value 52 ± 1° for stainless steel SS 304. Additionally, the surface structure of Ti-DLC film was analyzed after wear resistance testing via friction. It was revealed as a result of analysis that wear degree of film surface was rather low. Absence of defects, cracks and saving of definite degree of homogeneity of disordered film structure testify on its good wear resistance. The research was carried out under support of the RF President’s Grant Council (Agreement No. MD-2727.2022.4).