NANO-TRIBOLOGICAL INVESTIGATIONS OF CARBON OVERCOATS - CORRELATION WITH RAMAN-SPECTRA

Nano-indentation and nano-wear tests were performed on carbon overcoat s, which were deposited under different conditions on thin film magnet ic disks, using the point contact microscope (PCM). Two failure mechan isms of the overcoats during the nano-wear test are described: one is the wear of the carbon overcoat as measured by the wear depth; the oth er is the damage at the overcoat-substrate interface as indicated by t he critical cycle. The hardness of the carbon overcoat correlates well with the wear resistance. Also a certain relation between the Raman s pectra and mechanical properties of carbon overcoats is found. However , it is shown that the Raman spectra can not be used as the sole indic ator of the wear resistance of carbon overcoats.