Energy gradient carbon embedding in the magnetic media for improved tribological performance

• An energy gradient mixed layer in the top 1 nm of the media is fabricated.
• Scratch resistance of the media surface improved significantly after modification.
• The energy gradient mixed layer showed a very low coefficient of friction of ~ 0.2.
• It performed better than commercial media in terms of coefficient of friction.

A technique of energy gradient carbon embedding using the filtered cathodic vacuum arc technique in the top layer of the magnetic media is evaluated for its tribological properties. Cobalt is used as the magnetic material. The embedded layer is obtained by using ion energies of 60 eV and 90 eV successively to embed carbon in the top layer of the magnetic media and seal the Co/C mixed layer with a few mono-layers of carbon. Auger electron spectroscopy and transmission electron microscopy are used to characterize the modified surface in terms of its thickness, structure and chemical composition. Ball-on-disk wear tests and atomic force microscopy based scratch tests are conducted on the bare cobalt and modified cobalt surfaces to characterize the wear resistance. It is observed that the wear life and scratch resistance of the cobalt surface improved considerably after the surface modification.