| 摘要 |
PURPOSE:To obtain a permanent magnet which is small in magnetic fluctuation with a temperature change and is not lowered in coercive force even in a compaction treatment, by a method wherein particles of a porous aluminum oxide filled in its pores with a ferromagnetic metal or ferromagnetic alloy are compression-molded in a magnetic field and hardened. CONSTITUTION:An aluminum or aluminum-base alloy substrate is anodized to form a porous aluminum oxide film 6. A ferromagnetic metal or ferromagnetic alloy is desposited in the pores of the film by electroplating. This is finely ground to obtain a magnetic powder 4. Each ferromagnetic body 5 in the magnetic powder 4 has a diameter of about 0.01-0.04mum and a length of 0.1-1mum. The ferromagnetic bodies 5 are filled while aligning in one direction and are coated with the aluminum oxide 6. The magnetic powder 4 is compression- molded in a magnetic field and hardened to form a permanent magnet. In this case, the pressurizing direction and the magnetic field direction are made orthogonal to each other to obtain excellent magnetic characteristics. Further, a liquid organic resin is employed as an impregnating binder. The impregnation is carried out at an ordinary temperature or properly raised temperature and in the atmospheric air or under high-pressure conditions. |
