Evolution of Transferred Lubricant Distributions on the Slider Surface Under Ambient and Laser-Heating Conditions

The dynamic equilibrium among the condensation, evaporation and shear flow of the lubricant on a slider has been modeled by solving a continuum-based partial differential equation, with temperatures obtained from a finite element model. Zero-flux and specified-flux boundary conditions were used to study the trailing pad of a slider. The results show that the average lubricant thickness on the trailing pad gradually approaches a steady state, and the steady-state value increases with increasing disk lubricant thickness. A reduction of the flying height leads to a reduced steady-state slider lubricant thickness. The temperature rise of the disk surface tends to promote the lubricant transfer to the slider in a region close to the trailing edge. However, this effect may be locally suppressed by the laser-induced local thinning of the lubricant film on the disk.

Self-Protecting Disk Lubricant: D-MH2

In disk drives of current generation, the thickness of the disk lubricant has been reduced to the level of a sub-monomolecular film. For a mono- or a sub-monomolecular film of a perfluoropolyether terminated with a primary hydroxyl unit at both ends, each lubricant molecular chain is chemically bound to the carbon substrate at both termini, and if it has a hydrocarbon sector inserted at its center, the hydrocarbon sectors would assemble at the top of the film. They are thus poised most aptly to react as a Lewis base (an electron donor) to the Lewis acid centers on the slider thus abating the Lewis acid-catalyzed lubricant degradation. A TOF-SIMS study of lubricant films of various thicknesses was performed. The study substantiated the envisaged lubricant posture.

Disk Lubricants of Ultimate Design

In disk drives of current generation, the thickness of the disk lubricant has been reduced to the level of a sub-monomolecular film. For a mono- or a sub-monomolecular film of a perfluoropolyether terminated with a primary hydroxyl unit at both ends, each lubricant molecular chain is chemically bound to the carbon substrate at both termini, and if it has a hydrocarbon sector inserted at its center, the hydrocarbon sectors would assemble at the top of the film. They are thus poised most aptly to react as a Lewis base (an electron donor) to the Lewis acid centers on the slider thus abating the Lewis acid-catalyzed lubricant degradation.