Tribostimulated Gas Desorption from Thin Film Coatings of Amorphous Carbon in Ultra High Vacuum

Tribodesorption from hydrogenated amorphous carbon (a-C:H) coatings applied by methods of plasma-enhanced deposition from the gas phase, deposition from the ion ray and deposition using the cathode system is studied. Gas tribodesorption is investigated with the help of ultrahigh vacuum tribometer equipped with the quadrupole mass-spectrometer. Experiments have shown that under ultra low friction conditions the gas emission level is below the sensitivity of the available mass-spectrometer. However, the gas emission, mainly H₂ and CH₄, is observed with the growth of a friction factor in the process of the spontaneous termination of the ultra low friction conditions. The analysis of the surface shows the availability of damages while friction traces are practically absent under ultra low friction conditions. The gas emission is shown to have a clear connection with the ultra low friction conditions; thus, tribodesorption may be applied as a method of diagnosing the mechanism breakage.