Nanotribological evaluations of hydrogenated carbon films as thin as 5 nm on magnetic rigid disks

Nanotribological characterization techniques including nano-wear tests and nano-friction tests are used to evaluate mechanical and tribological properties of 5, 10 and 25 nm thick hydrogenated carbon films deposited as protective coatings on super smooth magnetic disks. Effects of film thickness and substrate materials are investigated. It is found that the film with a higher thickness has a larger critical cycle for film break-through. The 5 nm thick film has the smallest wear depth before the critical cycle, the largest critical load for wear, and the largest friction coefficient in the low friction regime. No significant differences are observed between the 10 nm and 25 nm thick films with respect to these three parameters. The film on the magnetic layer is removed with fewer wear cycles than on the silicon substrate. But the effect of substrate is not significant on the wear depth before the critical cycle, the critical load for wear initiation, and the friction coefficient in the low friction regime