Effects of Energetic Ion Particles on Friction of Diamond-Like Carbon

We demonstrate that energetic argon ions introduce phase transformation of a diamond-like-carbon film. Inside an ultrahigh vacuum chamber, energetic Ar ions of 5KeV were generated using an X-ray photon spectroscopy. After ion bombardment, the XPS and friction tests were conducted in situ. The ex situ surface morphological analysis using an atomic force microscope and the multiple-peaks deconvolution of the C 1s XPS peak indicate that the changing ratio of sp2 and sp3 hybridization of carbon dominates the film's friction. We conclude that the friction of the DLC film against itself depends on the carbon phase, not the film's surface roughness.