The Influence of Aluminum Oxide Particles in Magnetic Coating on Head/Disk Wear

Abstract

The particulate magnetic disks commonly used in magnetic disk storage systems contain aluminum-oxide (Al₂O₃) particles to reinforce the strength of their magnetic coating. In this paper, the influence of these particles on the tribological characteristics of particulate disks is investigated using two types of ferrite materials for flying heads and particulate disks with four different levels of Al₂O₃ content. As the Al₂O₃ content increases, the wear mode changes from the adhesive wear to the abrasive wear. Owing to this transition, the head wear becomes increasingly severe while the durability of the particulate disk improves. Regarding the differences between ferrite materials, relatively soft Mn-Zn ferrite shows worse wear results than hard Ni-Zn ferrite. In particular, it is found that Mn-Zn fertile is worn even by the γ-Fe₂O₃ particles of the particulate disks. In the combination of ferrite materials and particulate disks used here, an Al₂O₃ content of around 8 percent is optimum to avoid headcrash, which is one of the most serious problems in magnetic disk storage systems.