Tribocharging of the magnetic hard disk drive head-disk interface

As head-disk separation diminishes and the sensitivity of magnetic recording transducers increases, the effects of spurious charge buildup caused by friction become an increasing concern. We have investigated some of the characteristics of tribocharging during frictional contact between head and media typically found in magnetic hard disk drives. From constant velocity tests with an electrically isolated head contacting the laser texture zone, we find that current and voltage are closely related, both undergoing a rapid initial rise followed by a long-term rise. We have found that the long-term rise is controlled by the rate of discharge and that the overall magnitude of both current and voltage is dependent upon the rate of rotation. Additionally, we find that the magnitude of current and voltage increases sequentially from test to test, suggesting that wear is occurring at the interface. We develop models for wear-induced tribocharging and surface potential difference-induced tribocharging and contrast their predictions for charge generations as functions of velocity. These models suggest that wear is the dominant tribocharging mechanism. (C) 2002 American Institute of Physics.