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US 4,364,988 AGranted
Magnetic recording medium
AssigneeHitachi Maxell, Ltd.
InventorsHaruo Andoh, Susumu Kitaoka, Toshinobu Sueyoshi, Hikaru Ishida, Akira Kato
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AssigneeHitachi Maxell, Ltd.
InventorsHaruo Andoh, Susumu Kitaoka, Toshinobu Sueyoshi, Hikaru Ishida, Akira Kato
Estimating the term…
An improved magnetic recording medium is disclosed, particularly a magnetic tape suitable for sound recording and video recording, which comprises as a recording element a mixture of cobalt-containing iron oxide magnetic particles consisting essentially of ferromagnetic iron oxide particles containing cobalt and optionally a divalent iron in the most outer layer thereof, and .gamma.-ferric oxide particles in the ratio of 10:90 to 50:50 by weight, said mixture of cobalt-containing iron oxide magnetic particles and .gamma.-ferric oxide particles being applied to a substrate (e.g. a polyester film) with a binding agent. The magnetic recording medium has excellent electromagnetic transducing properties and improved charging properties and is useful for conventional magnetic recording apparatus used at normal position with high sensitivity in wide range of frequency.
A magnetic recording medium which comprises as a recording element a substrate with a single layer of a composition on the surface thereof comprising a mixture of cobalt-containing iron oxide magnetic particles consisting essentially of ferromagnetic iron oxide particles containing cobalt in the most outer layer thereof and .gamma.-ferric oxide particles, said cobalt-containing iron oxide magnetic particles and .gamma.-ferric oxide particles being mixed in the ratio of 10:90 to 50:50 by weight, said cobalt-containing iron oxide magnetic particles having a coercive force of 20 to 100 oersteds higher than the coercive force of the .gamma.-ferric oxide particles.
Dependencies are inferred from the claim text.