New materials in rigid disks

For several years the thin-film rigid disk, as used in Winchester drives, has played a leading role in the exploitation of new materials. This is the case not only as far as the magnetic layer is concerned, but also in all the other components of the disk's complex composite structure. The ever-increasing demands placed on the disk to satisfy tribological, durability and reliability criteria place emphasis on all the layers which contribute to the head-disk interface, and that does not only mean the layer at the air surface, but can involve those buried deep within the disk and their interfaces. Material properties must be linked with carefully optimised surface topography to meet the needs for low friction and wear in the contact start-stop process, when the head lands on the disk, together with resistance to damage from corrosion phenomena to give long life and high integrity data-storage. Performance in all these areas must be improved while, at the same time, the fundamental magnetic recording parameters of the disk must be able to achieve the exacting specifications placed by disk-drive designers for higher areal density of recorded information and improved signal-to-noise.<>