| 摘要 |
PURPOSE:To improve durability by using magnetic powder formed with a magnetic metallic layer essentially consisting of cobalt on the surface of the nucleus crystal consisting of oxide magnetic powder as an essential component for magnetic powder and specifying the coercive force and saturation flux density of the magnetic layer. CONSTITUTION:The magnetic powder of a magnetic recording medium provided with the magnetic layer contg. the magnetic powder and binder on a nonmagnetic base consists essentially of the magnetic powder formed with the magnetic metallic layer essentially consisting of the cobalt on the surface of the nucleus crystal consisting of the oxide magnetic powder and the coercive force thereof is specified to <=1,000 oersted and the saturation flux density thereof to >=1,800 gauss. the oxide magnetic powder to be the nucleus crystal of the magnetic powder is exemplified by iron oxide magnetic powder such as gamma-Fe2O3, Fe3O4 and the intermediate oxide thereof, cobalt-contg. iron oxide magnetic powder solutionized with the cobalt uniformly in the powder or contg. the same as the surface layer of the cobalt oxide, chromium oxide magnetic powder and hexagonal ferrite powder such as Ba, Sr, and Pb ferrite powder. |
