| 摘要 |
PURPOSE:To develop metal powder for magnetic recording having extremely little deterioration with the lapse of time and excellent magnetic characteristic by finely pulverizing an iron alloy incorporating one or two more Ni, Mn, Al and P and/or Si with a specific ratio. CONSTITUTION:After adding water solution mixedly incorporating FeSO4, NiSO4 and MnSO4 to NaOH aqueous solution and mixing it, by blowing the air, the solution is oxidized to make slurry incorporating Ni-Mn-containing iron alpha-oxy hydroxide. To this slurry, NaAlO2 aqueous solution and of FeSO4 aqueous solution are added and mixed, and again by blowing the air, this is oxidized to coat Al-containing iron alpha-oxy hydroxide on the outer periphery of the Ni-Mn- containing iron alpha-oxy hydroxide. Successively, to this slurry, phosphoric acid water solution or silicic acid aqueous solution is added to coat P or Si on outer periphery of the iron alpha-oxy hydroxide. After washing this slurry, drying and burning in the air, heating reduction is executed to this in gaseous H2 to manufacture the magnetic iron powder for magnetic recording having composition incorporating 1-5% Ni, 0.1-0.5% Mn, 3-15% Al and 0.3-1.5% P or S in terms of Fe to be 100. |
