Work-hardening of Ferrite Head Surfaces by Wear with Flexible Recording Media

The ferrite surfaces of rotating magnetic heads were found to have been work-hardened to different degrees depending upon the abrasiveness of the flexible recording media used. For the more abrasive tape, the work-hardening was less than for the less abrasive tape. Associated with the increase in microhardness was decreased signal read-back and increased incidence of surface “pull-outs.” These phenomena may be understood in the context of fracture mechanics where residual stress, resulting from plastic deformation of the ferrite, is predominant in the wear mechanism.