Anodic vacuum arc evaporation of graphite for depositing layers of tetrahedral amorphous carbon

Anodic vacuum arc evaporation was applied to deposit ta-C layers with thicknesses of 1.3–2.2 μm at high deposition rates of up to 18 nm/s. Building on prior work that was limited to a thickness of 0.8 μm due to high heat flux and adhesion issues, substrates with a high heat capacity and adhesion-promoting interlayers were used. Nanoindentation tests revealed hardness values ranging from 71 to 84 GPa and Young’s moduli ranging from 717 to 862 GPa for these layers. Raman spectrometry revealed an sp3 content of 68% to 75%. The layers are free of arc-typical droplets and have a very smooth surface. These results demonstrate that anodic vacuum arc evaporation, when combined with targeted thermal management and interlayer design, provides a scalable method of producing ta-C coatings for challenging mechanical or chemical engineering applications.