The comparison of structure and properties in DC magnetron sputtered and HiPIMS W-C:H coatings with different hydrogen content

Tribological behavior of hydrogenated W-C/a-C:H coatings deposited by three different sputtering techniques

“…4a) consisted of crystallites with the diameter in the range of ~20 nm elongated perpendicularly toward the substrate. It agrees with our earlier X-ray diffraction studies which reported textured structure in this coating [24]. At small additions of acetylene (Fig.…”

“…4b), texture disappeared and a nanocomposite structure consisting of the crystallites with the diameter of about 10 nm in an amorphous matrix was formed. Such crystallites were usually attributed to WC 1-x phase and the matrix to amorphous carbon [5,10,18] which agrees with our earlier studies [11,12,24]. Higher additions of acetylene (Fig.…”

“…8b) similarly as in DCMS deposited with large additions of acetylene and hydrogen. Despite lack of direct evidence (no difference in the Raman spectra from the pristine coating and in the wear track was observed), long run-in period, low CoF and wear suppression in DCMS and HiPIMS W-C:H coatings with higher amount of hydrogenated carbon point toward the formation of a continuous lubricious tribolayer similar to the tribolayers indicated in undoped a-C:H coatings [1,2,6,7,[19][20][21] and which was already identified in a number of earlier studies also in W-C:H coatings [10,18,23,24,35].…”

“…It was also found out that hydrogen incorporation into the carbon matrix caused reduction of the residual stresses and improved adhesion [18,23]. In our previous studies on W-C:H coatings prepared by hybrid sputtering by DCMS, HiPIMS as well as HiTUS methods, similar CoF values were obtained [8,11,12,24]. However, the influence of hydrogen addition during hybrid PVD-PECVD deposition on friction behavior of these coatings was only partially investigated up to now.…”

“…Coating structure and properties are usually related to the average hydrogen concentrations obtained at macroscale with the elastic recoil data analysis (ERDA)/ Rutherford backscattering (RBS), forward recoil elastic scattering (FRES) [19] or secondary ion mass spectroscopy (SIMS) measurements [18]. Our recent ERDA/RBS measurements on the above DCMS W-C:H coatings [24] indicated that maximum ~35 at% of hydrogen can be incorporated into the carbon matrix under studied conditions and acetylene/hydrogen addition range, and acetylene is more effective in hydrogenation than molecular hydrogen. This is in full agreement with the earlier studies [6,7,18].…”