METALLIC MAGNETIC POWDER FOR MAGNETIC RECORDING MEDIUM, AND METHOD OF MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a metallic magnetic powder suitable for an application type magnetic recording medium having a high recording density, wherein a level of a weathering resistance equivalent to a conventional one is maintained, while a saturation magnetization σs is high irrespective of a particle volume.

SOLUTION: The metallic magnetic powder for the magnetic recording medium is constituted as a powder which is composed of particles having a metallic magnetic phase and an oxide film with Fe or Fe and Co being a main component. Pending matters can be solved by preparing conditions that an average long axis length of the powder particle is 10-50 nm, an average particle volume containing the oxide film is equal to or less than 5,000 nm3, and (R+Al+Si)/(Fe+Co) atomic ratio calculated by using a value of a content amount (atomic%) of each element included in the powder particle is equal to or less than 20%. R is a rare-earth element (Y is treated as the rare-earth element also). This metallic magnetic powder is obtained by eluating a non-magnetic component after sintering by use of a complexing agent and a reducing agent.

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