The effect of chemical and surface properties of hydrogenated carbon overcoats on the tribological performance of rigid magnetic disks

The chemical and surface properties of hydrogenated carbon films were evaluated by using various surface and bulk analytical techniques. These properties were then related to the disks´ tribological performance. The techniques used included hydrogen forward scattering, Fourier transform infrared spectroscopy, Raman spectroscopy, resistance measurements, contact angle measurements, electron spectroscopy for chemical analysis, drag tests, and a chemical reactivity test. As the hydrogen content of the carbon films increased from 16 to 53%, the carbon bonding character changed from sp² to sp³. This change in chemical properties improved the film´s mechanical and physical properties, which, in turn, led to improved mechanical durability in the drag tests. Incorporation of H into the films passivated the carbon dangling bonds at the film´s surface. This change at the films´ surface prevented oxidation and improved the performance of the films in the chemical reactivity test