| 摘要 |
PURPOSE:To manufacture magnetic powder which is easily adjustable grain size and is excellent in denseness, magnetic characteristics, and corrosion resistance by adding a Cr compound to ferrous hydroxide as a raw material in the manufacture of metallic iron-based magnetic powder. CONSTITUTION:An aqueous solution containing FeSO4 and a Cr compound, e.g., Cr(NO3)3, etc., is added to a NaOH aqueous solution while stirring to form Fe(OH)2 suspension containing a Cr salt and having pH11 or more. Then, the suspension is heated, and an oxygen-containing gas, e.g., air, etc., is blown into the suspension to separate the needlelike particles of alpha-iron oxyhydroxide (alpha-FeOOH) which is in turn filtered, washed with water, and then dried. The dried needlelike particles are then reduced by hydrogen in an electric oven to manufacture metallic iron magnetic particles containing Cr. |
