Wear-Resistant Thin Films of Amorphous Carbon Nitride Prepared by Shielded Arc Ion Plating

Amorphous carbon nitride (a-C:N) thin films were synthesized by means of shielded arc ion plating using a graphite target and pure nitrogen gas. The mechanical properties and chemical structures of these a-C:N films were studied through nanoindentation and X-ray photoelectron spectroscopic analysis. Nanohardness of the a-C:N film prepared at a substrate bias voltage of 0 V was ≈10 GPa. It was increased to 13–14 GPa when the substrate was biased negatively in the range of -100 to -500 V. The a-C:N film prepared at a bias of -300 V was particularly wear-resistant such that the film did not wear at all when rubbed with a diamond tip at a contact force of 20 µN. This highly wear-resistant a-C:N film was found to contain almost equal amounts of two C-N phases: β-C3N4-like and graphitelike phases.