Factors affecting the durability of repeatedly stressed flexible magnetic recording media

Abstract

With the increasing data densities demanded of magnetic recording media, and in particular of floppy diskettes, wear and its effects on the durability of the media is becoming increasingly important. A consequence of the higher recording density is reduced magnetic layer thickness, and hence mechanical contact problems are more significant. In this investigation the wear and durability of diskettes of nominally the same formulation have been studied as a function of process burnishing time and state of lubrication. The study was conducted in commercial disk drives and in two forms of simulation test apparatus. Durability was found to increase with burnishing time to a maximum value and then decrease with further burnishing. Durability was also found to increase substantially with surface lubrication, but to be relatively unaffected by internal lubrication. A mechanism for the wear of flexible magnetic recording media is proposed consisting of three phases: initial plastic flow of the surface region, fatigue induced delaminative wear, and finally avalanche breakdown due to three-body action.