| 摘要 |
PURPOSE: Provided is a method for preparing a strontium ferrite magnetic substance for a dual molded magnet having high saturation magnetization and coercive force. CONSTITUTION: The method comprises the steps of mixing Fe2O3 and a salt of KCl and NaCl in a ratio of 1:1, heating it at 800 deg.C to prepare a spherical-shaped one, mixing Fe2O3 and SrCO3 in a ratio of 5.85 : 1 by mol, adding 0.12 mol of CaO, 0.12 mol of SiO2 and 0.08 mol of Al2O3 as an additive, mixing the mixture and a salt of KCl and NaCl in a ratio of 1:1, and heating it at 750-900 deg.C to prepare a strontium ferrite powder; adding 4 parts by weight of poly(vinyl alcohol)as a binder to the strontium ferrite powder; applying a magnetic field of 9 KOe with compressing it with a pressure of 1,500 Kgf; sintering the obtained molded one at 1,100-1,300 deg.C for 3 hours; and magnetizing the sintered one.
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