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Dispersion and Coating Perfection By Plasma Ashing

IP.com Disclosure Number: IPCOM000048665D
Original Publication Date: 1982-Mar-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Brown, CA: AUTHOR [+6]

Abstract

It is desirable to test a new dispersion for its quality before using it in the mass production of disks. By plasma ashing away the organic binder material and using scanning electron microscopy (SEM) techniques, the quality of the dispersion of the magnetic particles in the coating can be evaluated. The SEM analysis shows: a) The degree of clumping or agglomeration, i.e., how well the magnetic particles are dispersed. b) The magnetic particle alignment in the orienting magnetic field during coating. c) Major contamination with debris or defects. Furthermore, with the use of a mask and a profilometer, an accurate measurement of the coating thickness can be obtained.

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Dispersion and Coating Perfection By Plasma Ashing

It is desirable to test a new dispersion for its quality before using it in the mass production of disks. By plasma ashing away the organic binder material and using scanning electron microscopy (SEM) techniques, the quality of the dispersion of the magnetic particles in the coating can be evaluated. The SEM analysis shows:
a) The degree of clumping or agglomeration, i.e., how well the

magnetic particles are dispersed.
b) The magnetic particle alignment in the orienting magnetic

field during coating.
c) Major contamination with debris or defects.

Furthermore, with the use of a mask and a profilometer, an accurate measurement of the coating thickness can be obtained.

Factors a through c are important criteria for judging qualitatively the goodness of a dispersion. The ashing process does not alter the particle distribution or the magnetic properties of the particles in any way. Thus, although the ashing technique is destructive, it preserves the most important features for the dispersion analysis.

Aside from testing the dispersion quality, this technique can test the magnetic particles with regard to size, range, asperity ratio, etc. Thus, the technique can be used as a further screen for a new particle lot in a dispersion.

To obtain the ultimate value from the plasma ashing test, the following procedure is recommended. Two sections of the disk can be cut, one section being larger than the other. From the smaller section, samples one half inch time...