Fuji Photo Film Company, Limited

Noboru Zinbo

Toshihiko Miura

Noriko Inoue

A magnetic recording medium comprising a support and a magnetic layer containing an abrasive, a binder and ferromagnetic powder dispersed in the binder, wherein the magnetic layer has a thickness of from 20 to 500 nm, the abrasive has a Mohs' hardness of 5 or more and a relative abrasive velocity of less than 200, and value A of a relational expression A=K/Z of an average particle size K of the abrasive and the thickness Z of the magnetic layer is from 0.1 to 3.0.

Magnetic recording medium

Provided is a magnetic recording medium permitting the controlling of backcoat layer transfer to a magnetic layer surface, a reduction in dropout even when employing microgranular magnetic material, as well as good running stability, durability, and storage properties. The magnetic recording medium has a magnetic layer with a ferromagnetic powder and a binder on one surface of a nonmagnetic support and a backcoat layer with a nonmagnetic powder and a binder on the other surface of the nonmagnetic support. The nonmagnetic powder is an acicular particle having a mean particle diameter of 5 to 300 nm, and the backcoat layer includes water-soluble cations in a quantity of 100 ppm or less and water-soluble anions in a quantity of 150 ppm or less.

A ferromagnetic metal powder comprises: a metal portion comprising Fe; and an oxide layer around the metal portion, wherein the oxide layer comprises an iron oxide having magnetism such that the saturation magnetization is from 50 to 95 A.m /kg.

Ferromagnetic metal powder and magnetic recording medium using the same

Disclosed is a magnetic recording medium which comprises a support having provided thereon a magnetic layer containing at least a ferromagnetic powder and a diamond particle, wherein the diamond particle has an average particle diameter of from 3 to 200 nm and a variation coefficient of the particle diameter of from 3 to 60%.

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Kanagawa, Japan

Noboru Zinbo