DIP-COATING OF ULTRA-THIN LIQUID LUBRICANT AND ITS CONTROL FOR THIN-FILM MAGNETIC HARD DISKS

The conventional viscous-flow mechanism associated with the dip-coatin g technique for lubricant thickness control becomes ineffective for de position of ultra-thin films (< similar to 2 nm) required for hard mag netic disks. We have demonstrated that at least two important microsco pic mechanisms dominate the control of lubricant thickness in this thi ckness range. They are surface adsorption and diffusion of lubricant m olecules at the solid-liquid interface. Furthermore, it was also obser ved that too fast a pulling-up speed resulted in a more nonuniform lub ricant film onto the disk surface. This is due to disturbance of the m eniscus profile by viscous drag. The uniformity and/or the microstruct ure of lubricant layer deposited onto the disk surface will then affec t tribological performance.