| 摘要 |
PURPOSE:To enhance the weatherproofness and the corrosion resistance of the title magnet by a method wherein a rare-earth bonded-magnet molded product is impregnated with the low-viscosity solution of a thermoset resin or a thermoplastic resin under a reduced pressure or under a pressurized state after reducing a pressure, the solution is dried and hardened and the inner surface and the outer surface of the molded product are covered with resin films. CONSTITUTION:A rare-earth bonded-magnet molded product is housed in a lower-part vacuum container; the pressure of the container is reduced down to about 10<-2> to 10<-3>mmHg; the air is evacuated. A resin solvent solution whose viscosity has been adjusted to be low is housed separately in an upper-part vacuum container connected, via a valve, to the upper part of the lower-part vacuum container; the air existing in the solution and the air existing in the space at the upper part of the solution are removed sufficiently under a reduced pressure. Then, gaps in the molded product are impregnated with the degassed solution until the molded product is buried. An impregnation operation is performed at room temperature for 3 to 30 minutes; after that, an inert gas such as nitrogen gas or the like is introduced; a vacuum is broken; the molded product is taken out and dried at a comparatively low temperature at the boiling point or lower of a solvent; after that, the resin is hardened at an optimum thermal hardening treatment temperature. |
