Tribological degradation of head-disk interface in hard disk drives under accelerated wear condition

To further increase the areal storage density of hard disk drive, one solution is to reduce the spacing between the magnetic head and disk to sub-1-nm regime. Such ultra-low spacing introduces great challenges to tribological reliability in the head-disk 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 and thermal asperity sensors were used simultaneously to monitor the touch down dynamics before and after each cycle of the overdrive test 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.