PURPOSE: To obtain a permanent magnet having a desirable shape without reducing remarkably a magnetic characteristic by a method wherein a magnetic arrisotrapy is provided for a Mn-Al system magnet through a cold or a hot plastic working process, the foregoing magnet is smashed to pieces in liquid nitrogen and a resin molding is provided for the magnet in an intensive magnetic field.

CONSTITUTION: When a Mn-Al system magnet having an easily magnetized axis along a longitudinal direction, which is worked through a hot extruding process by cold swaging or at 600W700°C approximately, and which is crushed at a normal temperature, the undesirable influences like distortion, twin or the like are left in the magnet powder. As a result, a magnetic flux density is considerably lowered if the resin molding may be performed in the magnetic field. If the crushing may be performed in liquid nitrogen (-169°C), the defects are not remarkably introduced to the magnetic powder. On the other hand, if the resin molding is performed in the intensive magnetic field, a remarkable reduction of the magnetic flux density can be prevented and a permanent magnet having a desirable shape be obtained. According to the above constitution, because the metallic material becomes brittle in a low temperature and becomes easy to be crushed with a low energy, and further because a working distortion is not introduced and a moving of the atoms becomes difficult, any abnormal condition is not occured easily.