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Detection of Damages and Defects In Particulate Disk Media

IP.com Disclosure Number: IPCOM000050365D
Original Publication Date: 1982-Oct-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Anderson, LC: AUTHOR [+2]

Abstract

The present technique provides a visual indication of the existence of any iron oxide exposed at the surface of a magnetic recording disk. Potassium ferricyanide solution doped with copper is formulated as the detecting agent. This solution will turn the disk surface region into a distinct dark blue color wherever iron (in the iron oxide form) in the disk media is exposed at the surface. In a finished particulate disk, iron oxide is mostly dispersed in the sub-surface layers of the media. Therefore, this solution will detect mechanical wear damages and-or intrinsic defects that have the sub-surface layers exposed.

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Detection of Damages and Defects In Particulate Disk Media

The present technique provides a visual indication of the existence of any iron oxide exposed at the surface of a magnetic recording disk. Potassium ferricyanide solution doped with copper is formulated as the detecting agent. This solution will turn the disk surface region into a distinct dark blue color wherever iron (in the iron oxide form) in the disk media is exposed at the surface. In a finished particulate disk, iron oxide is mostly dispersed in the sub-surface layers of the media. Therefore, this solution will detect mechanical wear damages and-or intrinsic defects that have the sub-surface layers exposed.

These kind of damages and defects can neither be accurately identified by optical microscopy nor be practically identifiable by a scanning electron microscope (SEM). However, they could be very harmful to the bit storage capability and/or the physical integrity of the disk media.

The features detected by this method can be easily recorded by optical microscope, wet paper printing, laser scanner, etc. The application of this technique can:
1. enhance the disk media inspection capability in a

manufacturing environment, and
2. provide disk wear marking capability for system start/stop

test, flyability test and head-disk interference

failure analysis.

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