| 摘要 |
PURPOSE:To improve residual magnetic flux density, maximum energy product and a coersive force by setting content of Cu to a rather low degree and compositely adding adequate amount of B and Zr in the permanent magnet material of R-Co-Cu-Fe system. CONSTITUTION:A permanent magnet is composed, in the weight percentage, of REM (a kind or two or more kinds of rare earth element including Y) of 2.0- 3.0%, Cu of 2-6%, Fe of 15-25%, Zr of 1-5%, B of 0.001-0.5% and 0.001<=B/ Zr<0.1, and a remainder substantially consisting of Co. In a permanent magnet of R-Co-Cu-Fe system, when content of Cu increases, a coersive force is improved but a residual magnetic flux density is lowered and a maximum energy product cannot be increased. Therefore, in order to set a content of Cu to said range and prevent reduction of coersive force by lowered content of Cu, an adequate amount of B and Zr are compositely added and effect of such addition is promoted by addition of Zr. Thereby, a coersive force can be improved as much. |
