| 摘要 |
PURPOSE:To obtain a corrosion-proof Fe-B-R permanent magnet, on which treatment time can be cut down by not only improving the corrosion-proof property of a resist-coated Fe-B-R permanent magnet, but also by thinning off the resin-coated film. CONSTITUTION:After an Fe-B-R permanent magnet body has been ground, an aging treatment is conducted in a vacuum or inert atmosphere. Besides, by conducting a heat treatment in the atmospheric air or in an oxidizing atmosphere having the concentration of 0.1vol.% or higher, alpha-Fe is formed on a tetragon-phased surface layer which is exposed to the surface of the magnetic body, FeO and Fe3O4 are formed on the outside of the aforesaid surface layer, alpha-Fe2O3 is formed on the outermost layer, the grain boundary phase of exposed tetragonal crystal is changed to R2O3 (hexagonal), and the surface of the magnet is passivated. |
