THE ROLE OF SURFACE-PROPERTIES IN THE MECHANICAL PERFORMANCE OF THIN-FILM RIGID DISKS

The canasite substrate, with its fine microtextured surface, results in improved reliability at low flying heights and allows higher recording densities because of its mechanical toughness and isotropic surface. However, the inhomogeneities and surface asperities induced by the nature of its polycrystallinity not only affect the glide height performance, but also cause occasional failure in CSS performance. Innovative new cleaning and special surface treatment (SST) processes aimed at mechanical performance enhancement of canasite disks have been developed. The superior glide and tribological performance of these treated disks is described here. AFM measurements indicated a different appearance in surface morphology with the introduction of the SST process. Many isolated asperities protruding from the surrounding micro-pit surfaces were found on untreated canasite disks. These asperities can result in a reduced slider-to-disk spacing and a substantial degradation in glide and CSS performances. The isolated asperities and ridges were found to be smoothed out with the introduction of the SST process, as verified by the AFM study. A further SEM examination also concluded that the presence of these asperities introduces scratches along the CSS track which cause CSS failure.