Recent advances in the synthesis and application of amorphous carbon nitride: A new protective overcoat for computer hard disk surfaces

Using conventional magnetron sputtering of graphite in an argon/nitrogen plasma, one can synthesize amorphous carbon nitride coatings. By controlling the total pressure, the nitrogen partial pressure and the substrate bias during film growth, one can obtain amorphous carbon nitride with hardness ~25-30 GPa and surface roughness below 0.2 nm. When used as a wear protective coating on hard disks and steel surfaces, one achieves a wear life improvement of a factor of three to ten over conventional coatings such as titanium nitride and amorphous carbon, respectively.