Low friction coatings of diamond-like carbon with silicon prepared by plasma-assisted chemical vapor deposition

TLDR: Amorphous carbon-silicon (a-C-Si) coatings with smooth surface and adhesion to steel substrate were deposited at 550°C by a dc glow discharge method from reactant gases of CH 4, SiCl 4, H 2, and Ar at a deposition rate of 1-3 μm h −1.Diamond-like carbon was detected by laser Raman spectroscopy in the coatings as discussed by the authors.

Abstract: Amorphous carbon-silicon ( a –C–Si) coatings with smooth surface and adhesion to steel substrate were deposited at 550°C by a dc glow discharge method from reactant gases of CH 4 , SiCl 4 , H 2 , and Ar at a deposition rate of 1–3 μm h −1 . Diamond-like carbon was detected by laser Raman spectroscopy in the coatings with high hardness of Hv 2000 and more than 70 at. % carbon. Ball-on-disk type and Ohgoshi-type apparatuses were used to measure the tribological properties. Ball-on-disk tests revealed that the a –C–Si coatings showed a friction coefficient as low as 0.04 against steel with no lubricant in an ambient atmosphere of 70% relative humidity, which was one-third that of an i –C coating. The wear rate of the steel ball against the coated disk was an order and three orders of magnitude smaller than that against i –C coated and uncoated disks, respectively. Both types of tests showed that the wear rate of the a –C–Si coating itself was also very small.