| 摘要 |
PURPOSE:To improve environmental resistance and increase density and output of a composite magnetic powder having magnetoplumbite structure such as hexagonal ferrite by specifying the ratio of Fe/Ba constituting the magnetic powder. CONSTITUTION:Fine powder of hexagonal BaFe12O19 having magnetoplumbite structure is made to react with FeSO4, etc., in N2 gas atmosphere and the reaction liquid is filtered to obtain a precipitate. The precipitate is washed with water and dried to obtain the objective magnetic powder having magnetoplumbite structure, consisting of a composite material of hexagonal ferrite and spinel-type ferrite and having an easy magnetization axis perpendicular to the plane of the particle and having an Fe/Ba ratio of the constituent elements of >12, particle diameter of <0.15mum and coercive force of 500-2,000 oersted. A magnetic recording medium can be produced by applying the magnetic powder together with an organic binder to a desired substrate in dispersed state. |
