| 摘要 |
PURPOSE:To increase a saturated magnetizing force of magnetic powder and to reduce the aging of a coercive force, by a method in which iron oxide layers containing zinc and bivalent iron are formed on the surfaces of gamma-Fe2O3 particles used as nuclei and cobalt compound layers are formed on the surfaces of the iron oxide layers. CONSTITUTION:After gamma-Fe2O3 is dispersed in aqueous solution containing sodium hydroxide, aqueous solution containing ferrous sulfate and zinc sulfate is added therein, is stirred, is heated and again stirred. After aqueous solution containing cobalt chloride is added therein and is stirred, it is dehydrated and dried. Addition of Zn and Fe<2+> can obtain the equivalent saturated magnetizing force with addition of fewer/amount of Fe<2+>, as compared with the case in which only Fe<2+> is added. |
