| 摘要 |
PURPOSE:To produce a fine magnetic metal powder having high coercive force, saturation magnetic flux density, etc., and appropriate for a high-density magnetic recording medium. CONSTITUTION:An oxidizing gas is blown into a suspension of a ferrous salt and an alkali in water to obtain iron oxyhydroxide. The surface of the seed crystal consisting essentially of the iron oxyhydroxide is doped with a rare-earth compd. and/or a silicon compd., the single crystal is aged above the oxidation reaction temp., an oxidizing gas is again blown into the suspension to grow the iron oxyhydroxide crystal, the surface of the iron hydroxide is coated with a shape holding agent, and the crystal is heat-treated at 500-800 deg.C in a nonoxidizing atmosphere and then heated and reduced by a reducing gas to produce a magnetic metal powder. |
