Choosing Disk Lubricants

In disk drives, information is stored in a magnetic layer, which is protected against the frequent slider-disk contacts by a protective coating, usually amorphous carbon , and a thin film lubricant. The addition of even a single layer of lubricant molecules can improve the wear life by several orders of magnitude. Consequently, the correct choice of disk lubricant is critical to long term reliability of a disk drive product. To achieve higher recording densities in future disk drives, the flying height of the recording head and slider will need to be reduced considerably, perhaps to the point of continuous contact, resulting in more slider-disk contacts. Only enough room will exist in these future disc drives for a few atomic and molecular layers of overcoat and lubricant to protect the data stored in the magnetic media during the more frequent slider-disk contacts. With such atomically thin films, a good molecular understanding of lubricants is essential for making the right choice of a disk lubricant. In this paper, I discuss the issues faced in choosing a disk lubricant capable of meeting the severe tribological demands in future disk drives.