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Magnetic Drum Coating

IP.com Disclosure Number: IPCOM000098748D
Original Publication Date: 1959-Dec-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Brown, WR: AUTHOR [+2]

Abstract

A novel coating for magnetic memory disks and drums has been developed that is durable and has high magnetic properties. It is a water suspension of magnetic powder and sodium silicate. The powder used is Prince No. 108 natural magnetite (Fe(3)O(4)) that is ball milled for periods from 20 to 75 hours. It is then mixed with 25 parts Na(2)O:SiO(2) (1 to 3.22 ratio) and 25 parts Na(2)O:SiO(2) (1 to 2.9 ratio) and ball milled for one hour. The resulting suspension, after drying, contains about 59% Fe(3)O(4) by weight or 40% by volume.

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Magnetic Drum Coating

A novel coating for magnetic memory disks and drums has been developed that is durable and has high magnetic properties. It is a water suspension of magnetic powder and sodium silicate. The powder used is Prince No. 108 natural magnetite (Fe(3)O(4)) that is ball milled for periods from 20 to 75 hours. It is then mixed with 25 parts Na(2)O:SiO(2) (1 to 3.22 ratio) and 25 parts Na(2)O:SiO(2) (1 to 2.9 ratio) and ball milled for one hour. The resulting suspension, after drying, contains about 59% Fe(3)O(4) by weight or 40% by volume.

In applying, the surface to be coated is degreased with a hot detergent solution and abraded with silicon carbide paper. The final cleaning is with a sodium silicate solution. The disk is held flat in a vacuum chuck and the solution is applied by a steel doctor blade having a one mil gap. The coating is applied in an atmosphere of 85-95% relative humidity and then dried in air.

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