Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Including a second component containing structurally defined...
Patent
1989-10-19
1991-09-24
Thibodeau, Paul J.
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Including a second component containing structurally defined...
428694, 428900, G11B 2300
Patent
active
050513036
ABSTRACT:
A magnetic recording medium is disclosed, comprising a nonmagnetic support having thereon plural magnetic layers comprising ferromagnetic particles dispersed in a binder, said ferromagnetic particles consisting of an iron oxide or a cobalt-containing iron oxide, said plural magnetic layers comprising at least an upper magnetic layer and a lower magnetic layer, wherein said upper magnetic layer has a coercive force (Hc) of from 650 to 1000 Oe, a crystallite size of the ferromagnetic particles contained in said upper magnetic layer is less than 500 .ANG. as measured by a X-ray diffraction method, an average length in the long axis of the ferromagnetic particles contained in said upper magnetic layer is from 0.1 microns to less than 0.25 microns as measured by a transmission type electronmicroscope, said lower magnetic layer has a coercive force (Hc) of from 0.6 to 1.0 times that of said upper magnetic layer, a crystallite size of the ferromagnetic particles contained in said lower magnetic layer is larger than that of said upper magnetic layer and is in the range of 500 .ANG. or less, and an average length in the long axis of the ferromagnetic particles contained in said lower magnetic layer is larger than that of said upper magnetic layer and is in the range of from more than 0.1 microns to less than 0.25 microns.
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patent: 4851289 (1989-07-01), Ogawa et al.
Inaba Hiroo
Noguchi Hitoshi
Ogawa Hiroshi
Saito Shinji
Fuji Photo Film Co. , Ltd.
Thibodeau Paul J.
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