| 摘要 |
PURPOSE:To prepare magnetic powder having excellent magnetic properties and dispersibility, by preparing magnetic powder coated with a Co compound by the reaction of a dispersion containing iron oxide magnetic powder, a Co salt, a ferrous salt, and an alkali, at specific temperature, and further coating the powder with an alkylamine salt. CONSTITUTION:A dispersion containing iron oxide magnetic powder (e.g. gamma-Fe2 O3), a Co salt (e.g. CoCl2), a ferrous salt (e.g. FeCl2) and an alkali (e.g. NaOH), is made to react at <=50 deg.C, pref. 30-45 deg.C to deposite a Co compound on the nucleus crystal of the iron oxide magnetic powder. The magnetic powder coated with the Co compound is washed with water, filtered, immersed in an aqueous solution of an alkylamine salt (e.g. alkylamine acetate), and dried to obtain the magnetic powder coated with the alkylamine salt. The magnetic powder prepared by this process is useful as a recording element for a high-performance recording medium. |
