PURPOSE: To produce easily uniform and stable magnetic powder having high coercive force by precipitating ferromagnetic material in the pores of the film of nonmagnetic porous aluminum oxide by an electroplating method then grinding the film to fine particles.
CONSTITUTION: A base material 1 of aluminum or an aluminum alloy is anodized to form the film 2 of porous aluminum oxide 2a. A ferromagnetic material 3 of a ferromagnetic metal or ferromagnetic alloy is precipitated by an electroplating method in the many pores 2b which are parallel to the surface of the film 2 and are parallel with each other. The film 2 is separated by dissolving the base body 1 and is ground, whereby fine particles 4 that provide magnetic powder are obtained. Since the fine particles 4 hold the acicular ferromagnetic material 3 in the pores 2b of the nonmagnetic aluminum oxide 2a, the particles have a high coercive force characteristics and is free from the deterioration in the coercive force owing to the mutual magnetic effect among the particles and the sintering of the powder.
HOSHINO KOUICHI
KUMASAKA KAZUHIRO
KUBOTA SHIYOUZOU
