Method and apparatus for lubricating a magnetic disk continuously in a recording file

• US 4,789,913 A
• Filed: 08/03/1987
• Issued: 12/06/1988
• Est. Priority Date: 08/03/1987
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Murray, Bruce A., Rothschild, Wayne J., Gregory, Thomas A., Keller, Christopher G., Kennedy, Bruce E.
• Primary Examiner(s): Tupper, Robert S.
• Application Number:
  US07/081,271
• Time in Patent Office: 491 Days
• Field of Search: 360/69, 360/71, 360/97-99, 360/137
• US Class Current: 360/97.03
• CPC Class Codes: G11B 23/505 of disk carriers
• CPC Class Codes: G11B 33/148 Reducing friction, adhesion, drag

Abstract

In a magnetic disk file having a plurality of disks and a source of organic lubricant mounted within a housing, an air flow stream recirculates within the housing. The vapor pressure of the lubricant source is controlled to provide vapor phase transport of lubricant molecules between the source and the disks'"'"' recording surfaces. The lubricant molecules bidirectionally transfer between the air stream and the source, and between the air stream and the surface of the disks, as is needed to maintain a mono-molecular lubricant film, in the range of about 3 to 15 angstroms, on the disks in accordance with the principle of Langmuir kinetics. The disks are rigid disks and their recording surface includes a carbon overcoat. This overcoat has an affinity for the airborne organic lubricant molecules.

In a first embodiment, the vapor pressure of the lubricant is controlled by mounting the material at the coolest location within the housing.

In a second embodiment, the lubricant is carried as a mono-molecular layer of lubricant on granular carbon particles which have a surface area that is many times greater than the surface area of the disks.

In a third embodiment, the vapor pressure is controlled by combining the lubricant with a vapor pressure diluent.

Claims

1. A method for maintaining a mono-molecular layer of an organic lubricant on a recording surface, comprising:

providing a magnetic recording surface having an affinity for organic lubricant molecules,

coating said recording surface with a mono-molecular layer of an organic lubricant,

mounting said recording surface in container that is at least partially closed,

inducing an airflow stream within said container,

mounting a supply of an organic lubricant within said container and in said air stream at a location that is spaced from said recording surface, and

controlling the vapor pressure of said lubricant supply so as to establish a condition whereby said air stream (1) picks up lubricant molecules, (2) receives lubricant molecules, or (3) neither picks up nor receives lubricant molecules, from said lubricant supply and/or said recording surface, as is required to maintain said mono-molecular lubricant layer on said recording surface.

2. The method of claim 1 wherein said recording surface is a magnetic recording disk, and wherein said airflow stream is induced by rotation of said disk.

3. The method of claim 1 wherein said step of controlling the vapor pressure of said lubricant source comprises:

providing a cool temperature at said lubricant supply, relative said recording surface, to insure that said mono-molecular lubricant layer is maintained on said recording surface by operation of substantially equilibrium Langmuir kinetics, and that lubricant molecules do not transfer from said air stream to said recording surface by the process of condensation or the like.

4. The method of claim 3 wherein said recording surface is a magnetic recording disk, and wherein said airflow stream is induced by rotation of said disk.

5. The method of claim 4 wherein the temperature of said lubricant is at least 0.5°

centigrade cooler than the temperature of said recording surface.

6. The method of claim 5 wherein said mono-molecular lubricant layer is in the range of about 3 to 15 angstroms thick.

7. The method of claim 6 wherein said recording surface includes a carbon-containing overcoat layer.

8. The method of claim 1 wherein said step of controlling the vapor pressure of said lubricant source comprises:

providing a mass of granular carrier particles of very large surface area relative the area of said recording surface, said particles having an affinity for lubricant molecules, and

treating said carrier particles with said lubricant having an effective vapor pressure substantially identical to that of said mono-molecular layer on said recording surface,

to thereby insure that said mono-molecular lubricant layer is maintained on said recording surface by operation of Langmuir kinetics.

9. The method of claim 8 wherein said recording surface is a magnetic recording disk, and wherein said airflow stream is induced by rotation of said disk.

10. The method of claim 9 wherein the effective surface area of said carrier particles is at least 1000 times greater than the surface area of said recording surface.

11. The method of claim 10 wherein said mono-molecular lubricant layer is in the range of about 3 to 15 angstroms thick.

12. The method of claim 11 wherein said recording surface includes a carbon-containing overcoat layer, and wherein said granular particles are formed of a carbon-containing material.

13. The method of claim 1 wherein the vapor pressure of said supply of lubricant is controlled by

combining said lubricant with a diluent having a lower vapor pressure than said lubricant, to thereby produce a mixture whose bulk vapor pressure is substantially the same as the vapor pressure of a mono-molecular layer of said lubricant, to thereby insure that said mono-molecular lubricant layer is maintained on said recording surface by operation of Langmuir kinetics.

14. The method of claim 13 wherein said recording surface is a magnetic recording disk, and wherein said airflow stream is induced by rotation of said disk.

15. The method of claim 14 wherein said recording surface includes a carbon-containing overcoat layer.

16. The method of claim 15 wherein said mono-molecular lubricant layer is in the range of about 3 to 15 angstroms thick.

38. The method of claim 8 wherein the treating of said carrier particles comprises coating said carrier particles with a thin layer of said lubricant.

39. The method of claim 8 wherein the treating of said carrier particles comprises filling porosity within said particles with said lubricant.

17. Magnetic recording apparatus, comprising

magnetic recording media means including recording surface means having an affinity for organic molecules,

means for inducing flow of an air stream to said recording surface means,

a supply of a vaporizable organic lubricant material in said air stream at a location that is spaced from said recording surface means, and

means ensuring that the operating temperature of said lubricant supply is lower than the operating temperature of said recording surface means,

such that vaporization of said lubricant occurs in a manner to effect vapor transfer of said lubricant, by operation of Langmuir kinetics, from said supply to said recording surface means in order to maintain a mono-molecular lubricant layer on said recording surface means.

18. The apparatus of claim 17 wherein said vapor transfer provides a lubricant layer in the range of about 3 to 15 angstroms thick on said recording surface means.

19. The apparatus of claim 17 wherein said magnetic media means comprises a magnetic recording disk having a carbon overcoat.

20. The apparatus of claim 19 wherein said vapor transfer provides a lubricant layer in the range of about 3 to 15 angstroms thick on said carbon overcoat.

21. The apparatus of claim 17 wherein said magnetic media means comprises a disk file including a plurality of magnetic recording disks, and wherein flow of said air stream is induced by rotation of said disks.

22. The apparatus of claim 21 wherein said disks include a recording surface comprises a magnetic recording layer and an carbon containing overcoat.

23. The apparatus of claim 22 wherein said vapor transfer provides a very thin lubricant layer in the range of about 3 to 15 angstroms thick on said carbon overcoat.

24. Magnetic recording apparatus, comprising

magnetic recording media means including recording surface means having an affinity for organic molecules, said recording surface having thereon a mono-molecular layer of a vaporizable organic lubricant,

means for inducing flow of an air stream to said recording surface means,

bulk lubricant means in said air stream at a location that is spaced from said recording surface means, said bulk lubricant means comprising a single phase mixture of

said vaporizable organic lubricant, and

a diluent having a vapor pressure that is lower than the vapor pressure of said lubricant,

said bulk lubricant means having a vapor pressure that is lower than the vapor pressure of said organic lubricant,

to thereby provide a vapor pressure for said bulk lubricant means that is substantially the same as the vapor pressure of said mono-molecular layer on said recording surface,

such that vaporization of said bulk lubricant means occurs in a manner to effect vapor transfer of said lubricant from said bulk lubricant means to said recording surface means in order to maintain said mono-molecular lubricant layer on said recording surface means.

25. The apparatus of claim 24 wherein said vapor transfer provides a lubricant layer in the range of about 3 to 15 angstroms thick on said recording surface means.

26. The apparatus of claim 24 wherein said recording surface means comprises a magnetic recording layer having a carbon overcoat.

27. The apparatus of claim 24 wherein said vapor transfer provides a lubricant layer in the range of about 3 to 15 angstroms thick on said carbon overcoat.

28. The apparatus of claim 24 wherein said magnetic recording media means comprises a disk file including a plurality of magnetic recording disks, and wherein flow of said air stream is induced by rotation of said disks.

29. The apparatus of claim 28 wherein said disks include a recording surface comprises a magnetic recording layer and an carbon containing overcoat.

30. The apparatus of claim 29 wherein said vapor transfer provides a very thin lubricant layer in the range of about 3 to 15 angstroms thick on said carbon overcoat.

31. Magnetic recording apparatus, comprising

magnetic recording media means including a recording surface having an affinity for organic molecules,

a mono-molecular layer of an organic lubricant on said recording surface,

means for inducing flow of an air stream to said recording surface means,

organic lubricant supply means in said air stream at a location that is spaced from said recording surface means, said lubricant supply means comprising

a mass of granules having a total surface area at least 1000 times greater than the surface area of said recording surface, and

a mono-molecular layer of said organic lubricant covering the surface area of said granules,

such that vaporization of said lubricant layer on said granules occurs in a manner to effect vapor transfer of said lubricant, by operation of Langmuir kinetics, from said granules to said recording surface in order to maintain said mono-molecular lubricant layer on said recording surface.

32. The apparatus of claim 31 wherein said vapor transfer provides a lubricant layer in the range of about 3 to 15 angstroms thick on said recording surface.

33. The apparatus of claim 31 wherein said magnetic media means comprises a magnetic recording disk having a carbon overcoat, and wherein said granules are carbon granules.

34. The apparatus of claim 33 wherein said vapor transfer provides a lubricant layer in the range of about 3 to 15 angstroms thick on said carbon overcoat.

35. The apparatus of claim 31 wherein said magnetic media means comprises a disk file including one or more magnetic recording disks, and wherein flow of said air stream is induced by rotation of said disk.

36. The apparatus of claim 35 wherein said disks include a recording surface comprises a magnetic recording layer and a carbon containing overcoat, and wherein said granules are carbon containing granules.

37. The apparatus of claim 36 wherein said vapor transfer provides a layer in the range of about 3 to 15 angstroms thick on said carbon overcoat.