| 摘要 |
PURPOSE:To manufacture ferrite with superior magnetic characteristics as a magnetic material by using ball mills each made of a sintered hard alloy in mixing and pulverizing stags so as to minimize the amount of impurities entering ferrite powder from the mills. CONSTITUTION:In the manufacturing of ferrite as an MO.Fe2O3 type magnetic material contg. NiO, ZnO and Fe2O3, said starting materials are wet mixed by means of a ball mill made of a sintered hard alloy, and the slurry is dehydrated, filtered, dried and calcined at about 900 deg.C. The calcined body is wet pulverized again by means of a ball mill made of a sintered hard alloy, and the wet powder is dried. The resulting powder is mixed with a binder such as polyvinyl alcohol, press-molded and sintered at 1,240 deg.C. The amount of impurities entering ferrite powder from the ball mills in the mixing and pulverizing stages is extremely small, and high-quality ferrite with high sintering density, high electric resistivity, superior initial magnetic permeability and superior saturation magnetic flux density is obtd. |
