Effect of tribocharging on lubricant redistribution

In hard disk drives, lubricant is used to increase the durability of the head/disk interface by reducing wear and the potential for catastrophic failure if and when the slider contacts the disk during the operational mode of the drive. Typically, today´s disks are coated with both bonded and mobile layers of lubricant. It is desirable to maintain the original distribution of the mobile layer over the life of the drive in order to realize the expected reliability of the head/disk interface. However, this task is quite elusive as the distribution of the lube changes due to usage coupled with environmental and other effects. In this paper, we show that lubricant can also massively redistribute itself due to tribocharging. We also show that this behavior is quite dependent on the relative humidity of the system.