| 摘要 |
PURPOSE:To lessen not only the lowering of saturation magnetization and to improve magnetic coersive force but also to improve the filling density when magnetic powder is formed into a bonded magnet, and also to lessen the quantity of gas generating at the time of jet pulverization by a method wherein, after magnet material of rare earthiron based nitride has been pulverized by a jet pulverizer, the pulverized powder is finely powdered. CONSTITUTION:Magnetic material is pulverized into a suitable particle size by a jet pulverizer in which raw material particles, accelerated by the pressure fluid of the inert gas such as air, nitrogen, helium, argon and the like, desirably mixed gas of nitrogen and air, are pulverized by the collision between raw particles or by the collision against the wall of the pulverizer, and the subsequent pulverizing operation is conducted by a wet pulverizer. At this time, the range of particle size of a jet pulverizer is average particle diameter of 2.5 to 20mum, desirably 2.5 to 10mum. Subsequently, the above-mentioned material is finely pulverized to the average particle diameter of 1 to 3mum using a wet pulverizer. As a result, the lowering of saturation magnetization is small when compared with the fine powder manufactured by the pulverizing method heretofore in use, and coersive force can be improved. |
