ABSTRACT
When thinking of a disk drive, one picture that comes to mind is that of digital data bits stored on a spinning disk housed inside a device such as a computer, digital video recorder, or MP3 jukebox. The precision and reliability of these high speed rotating devices is, perhaps, one of the leading examples of micro electromechanical systems and nanotechnology at work today. For example, the magnetic recording read/write head floats on an air lubricated bearing just 10 nm away from the disk surface with a relative velocity, which is often about 10 m/sec. That is a shear rate of 1 billion m/sec, and, occasionally, the recording head contacts asperities on the disk surface. With the data track width decreasing below 200 nm, the tolerance of the spindle motor on which the disks are mounted must have increasing stiffness with vibration amplitudes that are well below the track width to minimize servo seek time and track following. Ball bearing spindle motors used in the past have reached their limit, and future high performance products are incorporating fluid dynamic bearing spindle motors. In addition, when there is a high relative velocity between metallic and insulating components, electrostatic charge generation and dissipation must be
controlled. Lubricants play a key enabling role in all of the above vital requirements for the disk drive industry, and fundamental understanding of the lubrication requirements and the detailed physical chemistry of their performance are essential to the advancement of the technology.
