Raman and resistivity investigations of carbon overcoats of thin-film media: Correlations with tribological properties

Tribological measurements have been performed on a series of carbon films deposited on untextured 95-mm magnetic disks by magnetron sputtering. Raman spectra and resistivity data of these films have been correlated to friction and wear performance. Tribochemical wear, as estimated by the rate of frictional buildup, is correlated to the G-band position in the Raman spectrum. Abrasive wear is best correlated to the I(D)/I(G) intensity ratio of the D and G bands, as well as to electrical resistivity. Interpretation of these data using structural models of amorphous carbon films is discussed.