| 摘要 |
PURPOSE:To make a permanent magnet having excellent magnetic characteristics, by casting an alloy so that the macro structure of a cast ingot is mainly a columnar crystal structure in the manufacture of a rare-earth permanent magnet in which an alloy mainly containg rare-earth elements and transition metals is heat-treated after melting and casting processes. CONSTITUTION:An alloy having a required composition is melted in an aluminum pot using a high-frequency melting furnace and then casted by an iron mold at 1500 deg.C, Suppose that a chill crystal zone is A, a columnar crystal zone is B and a cubic system crystal zone is C. An ingot is cut out each from each of the alloy casts A, B and C, applied with solution heat treatment at an optimum temperature between 1140-1180 deg.C, put into an aging process at 800 deg.C, and finally put into magnetic hardening. The magnetically hardened ingot is ground into powder to be kneaded together with an organic binder. The mixture is applied with press-forming in a magnetic field. A resin in the formed body is hardened heating appropriately, to be made into a magnet. |
