| 摘要 |
PURPOSE:To reduce the pressing pressure and improve the degree of orientation and green strength during the course of manufacturing a rare earth magnet by simultaneously and timely performing an electric discharge sintering process while field-oriented pressing is performed. CONSTITUTION:After a mold space formed of a die 1 and lower punch 2 is filled up with magnet powder 3, an upper punch 4 is inserted and lowered and, just before the powder 3 is compressed, a magnetic field is generated by means of an electromagnet coil 5 and magnetic substance yoke 6 so that the easily magnetized direction of the powder 3 is oriented in the pressing axis. Powder which is deviated from the direction of the magnetic field starts to appear due to the friction between the powder when the pressure application is started, but the powder is compression-formed by applying a high-frequency voltage across the powder 3 by using the upper and lower punches 4 and 2 as electrodes immediately before the degree of orientation starts to decline so that each particle being in contact with each other can be joined to each other by fusion by micro-discharge between each particle. Therefore, a formed body which is high in green strength and degree of field orientation can be obtained with lower pressing pressure. |
