Friction and wear of ion-implanted diamondlike carbon and fullerene films for thin-film rigid disks

Abstract

In this paper, DLC coatings on a rigid magnetic disk were ion implanted with nitrogen and carbon ions to improve their wear lives. Nitrogen and carbon ion implantation with a dose of 5×1015 ions cm−2 at 200 keV have shown significant improvements in the coefficient of friction and sliding wear life which suggests that ion-implanted DLCs may be more desirable overcoats. Microstructural examinations of implanted films show that these films are still amorphous with no long range order. Implanted DLC films also may be attractive as an overcoat for the slider surface. An approximately 20-nm-thick fullerene film, a new solid lubricant, was also deposited on the disk surface to reduce its friction and wear. Fullerene films exhibited lower friction, however, these readily formed a transfer film on the mating slider surface. Since any transfer and movement of the material at the head-disk interface is undesirable, fullerene films are not expected to be potential overcoats. Coefficient of friction of implanted DLC and fullerene films on a microscale was also measured and was found to be lower than that on macroscale. Microfriction values of unimplanted and implanted DLC films were comparable.