CHARACTERIZATION AND UNLUBRICATED SLIDING OF ION-BEAM-DEPOSITED HYDROGEN-FREE DIAMOND-LIKE CARBON-FILMS

Diamond-like carbon films with a thickness of 0.5 mu-m were deposited onto silicon and WC-Co cemented carbide substrates using mass-analyzed C-12 beams at an energy of 500 eV. The microstructure of these films was amorphous as determined with transmission electron microscopy. The Auger electron and Raman spectra were identical with those observed on hydrogenated amorphous carbon films although the hydrogen concentration of the films was below the detection limit (about 0.5 at.%) for forward recoil spectroscopy. The unlubricated sliding properties of these films on WC-Co cemented carbide were examined using hardened steel or Si3N4 as the counterparts. In both cases, low friction and wear were found in circumstances where untreated WC-Co substrate suffered from significant damage. In the case of the Si3N4 pin rubbed against the diamond-like film a very low friction coefficient of 0.06 and altered morphology of the wear scar on the diamond-like film were observed. In contrast, in the case of hardened steel on the diamond-like film the thin deposition was found on the steel surface, indicating material transfer between sliding surfaces which resulted in a friction coefficient of 0.14. In both cases the diamond-like film remarkably reduced the wear of the counterface.