Diamond-like films of tetrahedral amorphous carbon deposited by anodic arc evaporation of graphite

• Published in: Surface & coatings technology Vol. 477; p. 130305
• Main Authors: Scheffel, Bert, Zywitzki, Olaf, Kopte, Torsten
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2024
• Subjects: Anodic arc; Diamond-like carbon; Hollow cathode arc; Ta-C; Tetrahedral amorphous carbon; Vacuum arc evaporation; Anodic arc; Vacuum arc evaporation; Diamond-like carbon; Tetrahedral amorphous carbon; Ta-C; Hollow cathode arc
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2023.130305

A physical vapor deposition process using anodic arc evaporation in combination with a hollow cathode arc discharge was applied to the evaporation of graphite for deposition of hydrogen-free carbon layers. The diamond-like carbon (DLC) films deposited on 100Cr6 steel substrates were investigated by nanoindentation, Raman spectrometry, FE-SEM, AFM and spectroscopic ellipsometry. The relationships between the process parameters and the coating properties are discussed. Coatings deposited without bias voltage at substrate temperatures <200 °C are very hard (61–75 GPa) with also very high Young's modulus (588–685 GPa). The evaluation of the Raman spectra indicated a high proportion of tetrahedral sp3 bonds in the range of 70–88 %. Obviously, the vapor particle energies are high enough to achieve such high hardness values even without application of a bias voltage. The coatings proved to be completely droplet-free and have a very low surface roughness as confirmed by FE-SEM and AFM. The deposition rates in the range of 4–18 nm/s are exceptionally high for such tetrahedral amorphous carbon (ta-C) coatings, which is a good prerequisite for industrial applications. The ta-C layers with very high hardness and smooth surface are well suited as wear resistant layers. •Thin diamond-like carbon (DLC) films were deposited using an anodic vacuum arc.•The coatings are very hard (45–75 GPa) and have a high Young's modulus (416–685 GPa).•The Raman spectra indicate a proportion of tetrahedral sp3 bonds of 55–88 %.•The coatings proved to be completely droplet-free.•The coating rates in the range of 4–18 nm/s are exceptionally high for ta-C coatings.