Analysis of stain formation and wear mechanisms in a linear tape drive

Abstract

Abstract

Magnetic reliability of a linear tape drive is intimately related to the tribology at the head-tape interface because an increase in the spacing between the read element of the head and the magnetic particles in the tape reduces the strength of the magnetic signal read from the tape. In this study, Co-γ-Fe₂O₃ tape was worn against magnetoresistive (MR) heads in a modified commercial tape drive. Friction, the head output and the number of drop-outs were used to determine the wear mechanisms at the head-tape interface. Additionally, atomic force microscope (AFM) measurements, Auger material composition analysis and stain thickness measurement using a nanoindentation scratch test were used to support the friction and magnetic data. Using these methods, it was found that three different wear mechanisms occur at the head-tape interface, which first involves adhesion building a stain on the head surface, followed by the cyclic wearing and accumulation of the stain. Finally, the tape binder is sufficiently worn away, causing the stain to be permanently removed by abrasion of the hard magnetic particles. The life of the head-tape interface can be improved by cleaning the stain from the head with an abrasive tape before the stain becomes too thick. Therefore, if only one tape was used in the lifetime of the head, the head would need to be cleaned only once because the tape has a finite amount of stain-producing material available. However, if the stain thickness is reduced too much, the head-tape interface will not function without an increase in stain material because the presence of the stain provides lubrication without which the friction at the head-tape interface exceeds the motor force, causing the drive to stop.