| 摘要 |
PURPOSE:To obtain the permanent magnet at low cost, having large coercive force, which can be used at a high temperature even when temperature varies, by a method wherein the sintered body formed by adding a rare-earth oxide to a specific R-B-M alloy composition is used. CONSTITUTION:A sintered body is obtained by adding 0.1-15atom% of rare- earth oxide RmOn [values 2 and 3 are given to (m) and (n) excluding Ce, Pr and Tb, and the remainder is constituted by one or more kinds of Ce, Pr6O11, and Tb4O7] to the R-B-M alloy composition composed of rare-earth element R, boron B, iron and cobalt M at the following atomic percentage. R: 8-30%, B: 2-28%, and M: the remainder. As the crystal grain diameter of the sintered body is controlled by the rare-earth oxide, iHc is increased, and especially, the increase of Dy, Tb and Ho of heavy rare-earth is conspicuous. If the quantity of RmOn to be added to the R-B-M alloy composition is less than 0.1%, no effect is displayed, and if it is 15% or above, the deterioration of magnetic characteristics is remarkable. |
