Hydrocarbon Transfer in Disk Drives

In hard disk drives, oils used in the spindle motor or the actuator assembly are likely to be potential sources of hydrocarbon contaminants. Transfer to, and accumulation of such contaminants on the head would adversely affect its flyability. It was reported earlier that such transfer occurs more readily, the lower the vapor pressure of the contaminant is, and the lower the temperature of the ambiance is. The present study confirmed these findings. It is shown that the transfer is mediated by the disk surface area of high surface energy (openings of the carbon overcoat). Via an airflow transport process, droplets of the contaminant hydrocarbon are formed at such sites, and evolve in size till they are collected by the slider of the head.