| 摘要 |
PURPOSE:To obtain a magnetic powder which is excellent in corrosion-resistant property and whose saturation magnetization is high as a metallic magnetic powder and to obtain its proper manufacturing method by a method wherein metallic powder obtained by reducing an iron oxide-based powder in a vapor phase is hydrolyzed and treated in an organic solvent containing a specific component and it is heated and treated in the current of dilute oxygen. CONSTITUTION:This magnetic powder is formed in such a way that a ferromagnetic ferrite layer at 5 to 70vol.% with reference to a metal core composed mainly of iron is provided on the surface of the metal core. In the manufacturing method of the powder, an iron oxide-based powder as a raw-material is first reduced in a vapor phase, a metal powder composed mainly of iron is formed, and the metal powder is dispersed and hydrolyzed in an organic solvent with which an alkoxide containing a ferrite formation component has been mixed. Thereby, the hydrolyzed product of the alkoxide is applied to the surface of powdery particles; then, the particles are heated and treated in an inert gas containing a very small amount of oxygen gas; the magnetic powder provided with the ferromagnetic ferrite layer on the surface of the metal powder is obtained. Since, at the magnetic powder, a corrosion-resistant property is good, its saturation magnetization is high and it is provided with a very excellent property as a recording element for high-density recording use. |
