Tribological Degradation of Head–Disk Interface in Hard Disk Drives Under Accelerated Wear Condition

Abstract

To further increase the areal storage density of hard disk drive (HDD), one solution is to reduce the spacing between the magnetic head and disk to sub-1-nanometer regime. Such ultra-low spacing introduces great challenges to tribological reliability in the headdisk interface (HDI). Therefore, it is necessary to understand the characteristics and mechanisms of HDI degradation in the tribological condition. This paper investigates the degradation behaviors of HDI based on an accelerated wear experiment. Acoustic emission sensor and thermal asperity sensor were used simultaneously to monitor the touch down (TD) dynamics before and after each cycle of overdrive test in order to characterize the HDI degradation behaviors. Through analyzing the evolutions of HDI dynamic characteristics, the degradation mechanisms, including wear mechanism shift and HDI instability propagation, were figured out.

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“…It is known that the TDP will be increased if a significant amount of wear occurs at either the head or disk. Such phenomenon is due to the removal of the asperities during contact, hence allowing more mean-plane spacing between the head and disk that eventually requires additional thermal actuation to reach the TDP [24]. In order to differentiate head related wear and disk related wear, the accelerated wear test procedures were designed as follows [24]: 1) Load head at a reference track of the disk (see Fig.…”