MODIFICATION OF INTERFACIAL CHARACTERISTICS BETWEEN DIAMOND-LIKE CARBON-FILMS AND SUBSTRATES BY USING ION-BOMBARDMENT

Ion bombardment has been used to modify the interfacial characteristic s of diamondlike films produced by using a pulsed arc discharge deposi tion method. The films were deposited onto annealed unalloyed carbon s teel substrates. Two different structures were studied. In the first c onfiguration a 40 nm thick film was deposited directly onto a steel su bstrate. In the other case a buffer layer of SiC with a thickness of 2 0 nm was first deposited, followed by a deposition of a 40 nm thick di amondlike film. Both kinds of samples were exposed to ion bombardment of C-13 ions at an energy of 50 keV with the fluences of 10(15) and 5 x 10(15) ions/cm2. Ion bombardment did not result in any changes in th e adhesion of the diamondlike film without the buffer layer as determi ned by using a pull test. However, ion bombardment up to 5 x 10(15) io ns/cm2 of the sample with the SiC buffer layer improved the adhesion b eyond the testing capability of the pull tester. The results are discu ssed in terms of the thermodynamical properties and computer simulatio ns of the atomic movement at the coating/substrate interface. Prelimin ary tests on the effect of a high fluence of 10(17) ions/cm2 on the ad hesion of a diamondlike film on AISI 316 stainless steel were also per formed and the results, which are complemented with secondary ion mass spectroscopy (SIMS) measurements, are presented.