Formation of C-N-Si Film for Interlayer of Hard Material Coating by Pulsed Discharge Plasma CVD

Carbon nitride (C-N) and Si added C-N (C-N-Si) films were deposited on SKD61 steel plate by pulsed discharge (PD) plasma chemical vapour deposition (CVD). When the films were deposited with N2 and H2 diluted CH4 source gases, the deposition rate increased and the hardness decreased with increasing CH4 concentration. By means of adding mono-methyl-silane (MMS) gas to the source gases, the C-N-Si film having high hardness of 10 GPa and low Yung's modulus of 80 GPa could be deposited. The FT-IR spectrum of the films showed a peak of graphitic ring and peaks of terminating with H and N were observed. Raman spectra showed D and G peaks at around 1350 and 1590 cm−1, respectively. The intensity of D peak compared to G peak decreased when MMS was added. Ball on disk test of the C-N-Si film against SUJ2 ball showed the friction coefficient was about 0.2. These results shows that the C-N-Si film having high hardness and low Young's modulus, which is suitable for interlayer of hard film coating, can deposit by the PD plasma CVD, and suggest that the film is composed of fullerene-like structure which forms resilient and fracture tough materials.