| 摘要 |
PURPOSE:To manufacture ferro-magnetic iron oxide powder having a high magnetic reluctance and excellent frequency characteristics by the method in which needle- like Fe2O3 powder is added with stirring to a hydroxide precipitate suspension formed from a solution containing a specific amount of Co(II) and Fe(II) to convert the surface layer of the powder into ferrite, and subjecting the powder to filteration, drying, and heat treatment. CONSTITUTION:An alkali is added to a solution containing a 1:1.3 proportion of Co<2>+ and Fe<2>+ on the atomic basis to form a metal hydroxide precipitate composed of Cox13 Fe1-x/3 (OH)2(where x<=1,3), and needle-like ferro-magnetic Fe3O4 powder is added to the metal hydroxide precipitate suspension to oxidize the metal hydroxide with stirring to obtain the needle-like Fe3O4 powder whose surface has a Co ferrite layer composed of quantitatively formed CoxFe3-xO4 (where x<=1,3). Then, the Fe3O4 powder is filtered from the suspension and then subjected to heat treatment to obtain the needle-like ferromagnetic iron oxide powder composed of CoxFe3-xO4 (where x<=0.3) in which the distribution of metallic ion cancentration is uniform. |
