| 摘要 |
PURPOSE:To obtain metal magnetic powder having excellent uniform and close oxide film and oxidation stability without deteriorating magnetic characteristic by reducing acicular oxy-iron hydroxide or iron oxide and oxidation-stabilizing surface of the obtd. reducing material with N2O under gas phase. CONSTITUTION:The acicular oxy-iron hydroxide or the iron oxide containing iron as the essential component is reduced with H2 at about 450 deg.C. The surface of this reducing material is oxidation-stabilized with oxidizing gas under the gas phase. Then, as the oxidizing gas, N2O is preferably used and it is desirable to make low concn. at this initial stage of reaction and higher concn. according to progressing of oxidation in the range of about 0.1-100% in terms of N2, etc. Further, the reaction temp. is desirable to be at about 0-200 deg.C, particularly >=about 100 deg.C. By this method, the metal magnetic powder having excellent magnetic characteristic and oxidation stability is obtd. |
