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Teflon-Like FCOC Coating on Glide Heads for Stick-Slip Alleviation

IP.com Disclosure Number: IPCOM000015436D
Original Publication Date: 2002-Aug-17
Included in the Prior Art Database: 2003-Jun-20
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Abstract

With the current technology, as the hard disk areal density increases, the head-disk gap must decrease. As the distance between the head and the disk surface (hereinafter as “fly height”) decreases, molecular interactions between the head and the lubricated disk surface become increasingly dominant. The lubricant, head, and disk material all factor into determining the threshold fly height where the disk and head detrimentally interact with one another (hereinafter as “stick-slip height”). This interaction saturates the glide head piezoelectric transducer, resulting in false indications of disk topography anomalies and thus decreasing the glide head effectiveness. To counteract this phenomenon, a fluorinated carbon overcoat (FCOC) is applied to the head, resulting in a reduced stick-slip height, by as much as 33 percent. Reduction of the stick slip height allows lower fly heights and more accurate glide testing.

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Teflon-Like FCOC Coating on Glide Heads for Stick-Slip Alleviation

With the current technology, as the hard disk areal density increases, the head-disk gap must decrease. As the distance between the head and the disk surface (hereinafter as "fly height") decreases, molecular interactions between the head and the lubricated disk surface become increasingly dominant. The lubricant, head, and disk material all factor into determining the threshold fly height where the disk and head detrimentally interact with one another (hereinafter as "stick-slip height"). This interaction saturates the glide head piezoelectric transducer, resulting in false indications of disk topography anomalies and thus decreasing the glide head effectiveness. To counteract this phenomenon, a fluorinated carbon overcoat (FCOC) is applied to the head, resulting in a reduced stick-slip height, by as much as 33 percent. Reduction of the stick slip height allows lower fly heights and more accurate glide testing.

"Stick-slip" occurs when the head and the disk lubricant interact via Van der Waals forces. On a molecular level, when two materials are brought near one another, there is an attractive force, the strength of which is partially determined by the surface energy of each material. By manipulating the surface energies of the two materials, the amplitude of the forces in action may be altered.

The typical surface energy of the carbon overcoat of a head is approximately 50 erg/cm2. When the Teflon-like FCOC is applied to the head, the surface energy is reduced to approximately 12 erg/cm2. The surface energy of a typical hard disk is appro...