| 摘要 |
PURPOSE:To sinter many pieces of molded bodies in such a manner that the difference of magnetic characteristics is not generated by molding the material powders of a magnet contg. rare earth elements, boron and iron in a magnetic field, subjecting the same to a preheating treatment and thereafter sintering said molded bodies under specific conductions. CONSTITUTION:The material powders of the rare earth iron magnet consisting essentially of rare earth elements, boron and iron are molded to the prescribed shape in the magnetic field. Many molded bodies are then arranged on a calcining jig, are warmed to the temp. range from the temp. 100 deg.C lower than the sintering temp.-the temp. 10 deg.C lower than the sintering temp. at 5-50 deg.C/min temp. rising rate and are retained for >=5min to make uniform the temp. of whole molded bodies. Upon ending of said preheating treatment, the molded bodies are warmed to 1,000-1,200 deg.C sintering temp. at 1-10 deg.C/min temp. rising rate, are retained for about 0.5-6hr and are thereafter quenched. By this method, the whole molded bodies are uniformly sintered for prescribed hours in a sintering furnace and the lowering and dispersion of magnetic characteristics are drastically reduced. |
