| 摘要 |
PURPOSE:To unnecessitate the removing process for the coated layer as well as to improve the mass productivity for the subject permanent magnet by a method wherein a super thinned heterogeneous face layer is obtained on the surface of a sintered substance by utilizing the magnet manufacturing method of closed sintering wherein the evaporation of a rare-earth is suppressed. CONSTITUTION:The powder having rare-earth metal and cobalt as main ingredients is soaked in the medium such as toluene and the like, and the soaked superfine powder is formed into the desired shape using the so-called wet-type magnetic field forming machine. Then, the molded substance is placed in an airtight container and the formed substance, together with the container, is sintered at the approximate temperature range of 1,100-1,300 deg.C for about ten min. After the sintering was finished, the above is quickly cooled at the temperature ranging from the sintering temperature to the approximate temperature of 900-1,000 deg.C, and then slowly cooled at the temperature lower than the above. The cooling temperature differs according to the composition of the formed substance. The permanent magnet is obtained by magnetizing the sintered magnet, using an electromagnet. As the thickness of the coated layer of the sintered magnet thus obtained is several mum-50mum, the machining work for removal of the coated layer is unnecessary, and the permanent magnet can be manufactured with excellent mass productivity. |
