Lubricant Spin-Off from Magnetic Recording Disks

As the rotation rate of magnetic recording disks increases over the next few years, lubricant spin-off from the disk surface may be significant. Lubricant thickness was measured as a function of spin time at 10 000 rpm on typical carbon overcoated magnetic recording disks initially lubricated with 10–135 Å of perfluoropolyether Zdol. The viscosity of the lubricant film increased as the film thickness decreased with spin time. Lubricant spin-off in response to air shear stress on the free surface was approximately described by viscous flow. The rate of lubricant removal by evaporation was compared to the spin-off removal rate in films between 10 and 50 Å thick. Dispersion interaction and chemisorption are expected to retain a molecularly thin film of lubricant on the disk surface.

[1]  Robert E. Wilson,et al.  Fundamentals of momentum, heat, and mass transfer , 1969 .

[2]  Myung S. Jhon,et al.  Spreading of perfluoropolyalkylether films on amorphous carbon surfaces , 1999 .

[3]  H. S. Nagaraj,et al.  Evaporation and Flow Properties of Several Hydrocarbon Oils , 2000 .

[4]  B. Wolf,et al.  Temperature and pressure dependence of the viscosities of perfluoropolyether fluids , 1987 .

[5]  K. Sakai,et al.  Study of aerodynamic characteristics in hard disk drives by numerical simulation , 2000, 2000 Asia-Pacific Magnetic Recording Conference. Digests of APMRC2000 on Mechanical and Manufacturing Aspects of HDD (Cat. No.00EX395).

[6]  J. Hirschfelder,et al.  The transport properties of gases and gaseous mixtures. , 1949, Chemical reviews.

[7]  T. Karis,et al.  Surface Potential and Magnetic Recording Media Tribology , 1997 .

[8]  T. Karis,et al.  Calculation of spreading profiles for molecularly-thin films from surface energy gradients , 1999 .

[9]  H. Kubota,et al.  Density and viscosity of linear perfluoropolyethers under high pressures , 1989 .

[10]  S. Middleman The effect of induced air‐flow on the spin coating of viscous liquids , 1987 .

[11]  D. Grainger,et al.  Fluorinated surfaces, coatings, and films , 2001 .

[12]  Samuel Glasstone,et al.  The Theory Of Rate Processes , 1941 .

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

[14]  A. Adamson Physical chemistry of surfaces , 1960 .

[15]  T. Karis Tribochemistry in contact recording , 2001 .

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

[17]  M. Toney,et al.  Calibrating ESCA and ellipsometry measurements of perfluoropolyether lubricant thickness , 1998 .

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

[19]  J. Smith,et al.  Introduction to chemical engineering thermodynamics , 1949 .

[20]  F. Heslot,et al.  Spreading at the microscopic scale , 1990 .

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

[22]  T. Maruyama,et al.  An analysis of disk flutter in hard disk drives in an aerodynamic simulation , 2000, 2000 Asia-Pacific Magnetic Recording Conference. Digests of APMRC2000 on Mechanical and Manufacturing Aspects of HDD (Cat. No.00EX395).

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

[24]  S. Perry,et al.  HOW DISJOINING PRESSURE DRIVES THE DEWETTING OF A POLYMER FILM ON A SILICON SURFACE , 1999 .