Chemical contamination at the head-disk interface in a disk drive

Contamination of the head-disk interface (HDI) is known to degrade the performance of the disk drive. Through decades of ongoing improvements the level of airborne chemical contamination, although measurable, is extremely low in today\´s disk drives. Yet, exposure to aggressive environments can still produce droplets of liquid contamination at the HDI. This can cause increased startup friction or "stiction" at the interface of a disk drive. Previously reported chemical-induced stiction is reviewed. The outgassing within a disk drive is made up of a complex mixture of organic chemicals, but the liquid found at the HDI interface in experimental, but complete, drives is found to be principally composed of simple alkanes. The growth and movement of these alkane droplets at the HDI in a fully functioning disk drive was observed with a visualization setup, which can continuously monitor the HDI between a slider and a carbon-coated, lubricated glass disk.