| 摘要 |
PURPOSE:To provide hard ferrite with a high magnetic characteristic by a simpler process and to easily obtain a target magnetic characteristic by a method wherein only required quantites of SiO2 and Al2O3 out of additives which are added in a composite manner are left as iron oxide in the stage where iron ore is refined. CONSTITUTION:A hard ferrite is manufactured in such a way that its fundamental composition in terms of the molar ratio of Fe2O3/MO (where M represents Sr or Ba) is 5.3 to 6.3. In this case, an iron ore which contains 0.25 to 0.5wt.% of SiO2 or 0.2 to 0.5wt.% of Al2O3 or a refined iron ore obtained by refining the ore so as to obtain the content of SiO2 or Al2O3 is used as a raw material for ferric oxide. Then, 0.1 to 1.2wt.% of CaO is added, and, after that, this mixture is baked. For example, a refined iron ore which contains 0.3% of SiO2 and 0.26% of Al2O3 is used, SrCO3 is added so as to obtain the molar ratio of Fe2O3/SrO=6.00. This mixture is crushed, mixed and calcined. Then, 0.9wt.% of CaO is added. This mixture is crushed fine; after that, it is molded and baked. |
