Surface Roughness and Lubricant Depletion on a Magnetic Storage Disk

Abstract

It is widely believed that surface roughness of magnetic storage disks plays an important role in retaining the lubricant layers on the disks. Descriptions of the surface asperities of the disks, however, are so complex that it would be necessary to draw upon statistical techniques for an adequate representation. The purpose of this investigation is to evaluate the effect of surface roughness on lubricant retention by methods of stochastic simulation. It is found that surface roughness markedly enhances the retention of a thin liquid film on a rotating disk; the thinner the lubricant layer the more dominant is the effect of surface roughness. Moreover, different topographic structures of the surface roughness lead to different asymptotic limits of liquid retention.