Thin protective film for magnetic discs

A thin film of hexamethyldisiloxane, C/sub 6/H/sub 18/Si/sub 2/O, is deposited on a magnetic disk to protect its thin-metal-film medium. The comparison of the overcoat is analyzed using electron-spectroscopy chemical analysis (ESCA) and Auger profiling. It is found that upon polymerization, carbon, silicon, and oxygen are uniformly distributed in the film except in the near-surface layer of 3-5-nm thickness, where the carbon content is increased. Despite the differences in protective film thickness the value of the dynamic friction coefficient is practically constant (0.13-0.15), whereas the measured values of the static friction coefficient mu /sub s/ vary from 0.16 to 0.75. The value of mu /sub s/ and the composition of the film surface layer are well correlated; the lowest value of mu /sub s/ corresponds to the highest carbon content in the surface layer.<>