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Browse Prior Art Database

Plasma Ashing of Hard File Magnetic Disk Coatings

IP.com Disclosure Number: IPCOM000046274D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Erickson, GD: AUTHOR

Abstract

Plasma ashing is a technique which volatilizes the binder material from the coating of a magnetic disk, leaving only the magnetic iron oxide fibers and other inorganic asperities intact. Absence of the binder from the coating also allows easy removal of the coating from the aluminum substrate. The ashing technique can help microscopically analyze the coating by improved microscopic resolution wherein iron oxide fiber and asperity size can be measured, iron oxide fiber orientation can be evaluated, dispersion of the iron oxide fibers can be observed, and the density of the iron oxide fibers determined.

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Plasma Ashing of Hard File Magnetic Disk Coatings

Plasma ashing is a technique which volatilizes the binder material from the coating of a magnetic disk, leaving only the magnetic iron oxide fibers and other inorganic asperities intact. Absence of the binder from the coating also allows easy removal of the coating from the aluminum substrate. The ashing technique can help microscopically analyze the coating by improved microscopic resolution wherein iron oxide fiber and asperity size can be measured, iron oxide fiber orientation can be evaluated, dispersion of the iron oxide fibers can be observed, and the density of the iron oxide fibers determined.

Coating removal enables substrate surface inspection for such defects as asperities, etch pits, surface finish, scratches, and gouges. Implemented to a larger scale, the technique could be used for salvaging substrates of disks having an unusable coating.

The plasma ashing process may be conducted using commercially available equipment with an atmosphere of FREON-l4*. Oxygen may be used as an alternative atmosphere, but will result in a lengthened process time. Exposure of the samples is for limited times repeated at intervals to prevent overheating and possible reorientation of the fibers. Typically one to four l0-minute exposures are used separated by 5-minute intervals. The number of exposures and the exposure time are a function of the coating thickness and, also, sample size.

* Trademark of E.I. du Pont de Nemou...