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-coating technique for lubricant thickness control becomes ineffective for deposition of ultra-thin films (<~2 nm) required for hard magnetic disks. We have demonstrated that at least two important microscopic mechanisms dominate the control of lubricant thickness in this thickness range. They are surface adsorption and diffusion of lubricant molecules at the solid-liquid interface. Furthermore, it was also observed that too fast a pulling-up speed resulted in a more nonuniform lubricant film onto the disk surface. This is due to disturbance of the meniscus profile by viscous drag. The uniformity and/or the microstructure of lubricant layer deposited onto the disk surface will then affect tribological performance