Structural and mechanical properties of W-C: H coatings prepared by HiTUS

Abstract

The structure and mechanical properties of hydrogenated tungsten-carbon (W-C: H) coatings have been studied as a function of the composition and structure. These coatings were prepared by the High Target Utilization Sputtering (HiTUS), the first time used for this type of coatings. W-C: H coatings were deposited from tungsten–carbide target in argon, argon–acetylene (C2H2), and argon–methane (CH4) atmosphere on bearing steel 100Cr6 substrate, Al substrate, Si wafer a, and WC-Co substrate. W-C: H coatings obtained at different acetylene and methane flow were characterized by Elastic Recoil Detection Analysis (ERDA) and Rutherford Backscattering (RBS), X-ray diffraction, Transmission electron microscopy (TEM), and nanoindentation. Mechanical properties of these coatings are controlled within a range through a change in mutual concentration of crystalline phase and amorphous hydrogenated carbon matrix. The higher hardness (Hit = 29.5 ± 4.5 GPa) was measured for coating with 3 sccm methane addition. W-C: H coatings with more than 4 sccm of C2H2 and CH4 addition had fully amorphous structure and worse off mechanical properties.