Formation of lubricant “moguls” at the head/disk interface

In a typical head/disk interface of a rigid disk drive, the motion and redistribution of a 14 Å thick lubricant film on the disk under a flying slider is analyzed with an optical surface analyzer. At short times (∼seconds to a few minutes), the film is rearranged in an isotropic manner, creating a pattern of “moguls”1 of ∼100 μm in lateral size and a few angstroms in height. A strong correlation is demonstrated between the resulting distribution of the lubricant film and the underlying substrate topography. Surprisingly, lubricant becomes thicker on the peaks of the micro-waviness, and thinner in the valleys. Possible mechanisms for this unexpected behavior will be discussed, as well as its tribological implications. At longer times, the lubricant film is pushed away from underneath the slider, creating the previously reported circumferentially depleted tracks beneath the slider rails. In the timeframe of our experiment, no significant net lubricant loss was observed.

[1]  Bharat Bhushan,et al.  Tribology and Mechanics of Magnetic Storage Devices , 1990 .

[2]  Bruno Marchon,et al.  Complex terraced spreading of perfluoropolyalkylether films on carbon surfaces , 1999 .

[3]  C. Mathew Mate,et al.  Application of disjoining and capillary pressure to liquid lubricant films in magnetic recording , 1992 .

[4]  V. Novotny,et al.  Lubricant dynamics in sliding and flying , 1991 .

[5]  M. Forcada Instability in a system of two interacting liquid films: Formation of liquid bridges between solid surfaces , 1993 .

[6]  B. Bhushan Tribology and mechanics of magnetic storage systems , 1990 .

[7]  R. Waltman,et al.  Concerning the Interactions between Zdol Perfluoropolyether Lubricant and an Amorphous-Nitrogenated Carbon Surface , 1998 .

[8]  Bo Liu,et al.  An experimental study of slider vibration in nanometer spaced head-disk interface , 1999 .

[9]  Frank E. Talke,et al.  Identification of slider/disk contacts using the energy of the acoustic emission signal , 1998 .

[10]  Christenson Capillary condensation due to van der Waals attraction in wet slits. , 1994, Physical review letters.

[11]  Hal J. Rosen,et al.  Optical Surface Analysis of the Head-Disk-Interface of Thin Film Disks , 1995 .

[12]  David B. Bogy,et al.  Vibration of head suspensions for proximity recording , 1998 .

[13]  Polymolecular adsorption and capillary condensation in narrow slit pores , 1976 .

[14]  Myung S. Jhon,et al.  Spreading Profiles of Molecularly Thin Perfluoropolyether Films , 1999 .

[15]  Robbins,et al.  Thin liquid films on rough or heterogeneous solids. , 1991, Physical review. A, Atomic, molecular, and optical physics.

[16]  Zhu Feng,et al.  A study of tribo-charge/emission at the head–disk interface , 1999 .

[17]  Maté,et al.  Shear response of molecularly thin liquid films to an applied air stress , 2000, Physical review letters.