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SELF-LUBRICATING POROUS SIEVE HARD DISK DRIVE HEAD FOR DASD AND TAPE FILES

IP.com Disclosure Number: IPCOM000014242D
Original Publication Date: 2000-Apr-01
Included in the Prior Art Database: 2003-Jun-19
Document File: 1 page(s) / 27K

Publishing Venue

IBM

Abstract

A self-lubricating head which supplies a moderately low vapor pressure lubricant to the rails and pads has been designed to overcome stiction and wear effects during intermittent contact of the head and disk/tape system for files designed in contact or near-contact recording. The lubricant is contained within the micro-porous structure of the RIE etched cavity of the head surface. During file operation the lubricant slowly evaporates out of these pores and sieve holes to condense from a molecularly smooth film onto the air bearing pads and rails. One or more mono-layers of critical lubricant that is deposited prevents the deleterious action of stiction and wear effects normally seen with non lubricated heads. This promotes stable flying over the life of the product and insures more reliable product. A recording head is typically made of a hard ceramic material which has special surface features to enable air bearing regions for flying in close proximity to a rigid disk or tape system. As the flying height decreases between the head and disk/tape the probability of intermittent contacts increases. Vibration or pressure changes in the drive system typically will cause the head to actually come into contact with the surface medium. The disk or tape medium is usually lubricated with a high molecular weight, low oxidizable film of liquid which is typically 10 Angstroms to 100 Angstroms in thickness. This lubricant layer usually acts as a boundary lubricant and serves to prevent stick/slip and galling effects between the medium and the head. The problem arises when the medium is exceptionally smooth and the lubricant layer is extremely thin (less than 10 Angstroms). The lubricant tends to be selectively deposited to different thickness by the action of the airflow across the viscous boundary layer and the shear action of the flying head. The RIE etched area below the air bearing surfaces is modified to absorb the lubricant that will act to self-lubricate the drive for the life of the file. The surface roughness of this area is increased to allow larger surface area to form bonding surfaces for the lubricant to adhere to. In addition, micro-pore holes are etched into this area to constitute capillary holes for long term deposition of the desired lubricant. The invention alters the surface geometry and area of a typical recording head to form high surface roughness and micro-pore areas to form capillary holes for absorption of lubricant. This lubricant aids in the formation of a mono-molecular layer of boundary lubricant. The lubricant will slowly evaporate and condense out on the air bearing pads to form a Langmuir-Blodgett film. The lubricant will then prevent high stiction and wear effects from occurring during the life of the file. The invention solves the problem of head crashes during intermittent contact with the disk surface. The tribological action of the lubricant serves to protect the head and the disk surface from stiction and galling effects. 1

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  SELF-LUBRICATING POROUS SIEVE HARD DISK DRIVE HEAD FOR DASD AND TAPE FILES

   A self-lubricating head which supplies a moderately low vapor pressure
lubricant to the rails and pads has been designed to overcome stiction and wear
effects during intermittent contact of the head and disk/tape system for files
designed in contact or near-contact recording. The lubricant is contained within
the micro-porous structure of the RIE etched cavity of the head surface. During
file operation the lubricant slowly evaporates out of these pores and sieve holes
to condense from a molecularly smooth film onto the air bearing pads and rails.
One or more mono-layers of critical lubricant that is deposited prevents the
deleterious action of stiction and wear effects normally seen with non lubricated
heads. This promotes stable flying over the life of the product and insures more
reliable product.

A recording head is typically made of a hard ceramic material which has special
surface features to enable air bearing regions for flying in close proximity to a
rigid disk or tape system. As the flying height decreases between the head and
disk/tape the probability of intermittent contacts increases. Vibration or
pressure changes in the drive system typically will cause the head to actually
come into contact with the surface medium. The disk or tape medium is usually
lubricated with a high molecular weight, low oxidizable film of liquid which is
typically 10 Angstroms to 100 Angstroms in thickness. This lubricant layer
usually acts as a boundary lubri...