| 摘要 |
PURPOSE:To improve the dispersibility and the orientational property by magnetic powder as well as to obtain the magnetic recording medium having excellent magnetic characteristics and durability by a method wherein a non-magnetic metal oxide film is formed on the grain surface of the magnetic powder. CONSTITUTION:A non-magnetic metal oxide film is formed on the grain surface of the oxide magnetic powder such as barium ferrite magnetic powder, for example. As the non-magnetic metal oxide film, an oxide consisting of a metal having base oxidation-reduction potential, which is ordinarily -1.0--0.2V or thereabout, is considered desirable, because a film can be formed easily with this material. Ordinarily, the desirable quantity of adhesion of the oxide film for the magnetic powder is 0.3-5.0pts.wt. in metal conversion for 100pts.wt. of the magnetic powder. If this quantity is too small, the expected effect is not obtained, and if it is too much, the uniformity of film and the magnetic characteristics are deteriorated. By providing the above-mentioned non-magnetic metal oxide film, the magnetic interaction between grains of the magnetic powder can be made weaker without performing a surface treatment using an interface activator, thereby enabling to obtain excellent affinity and integrity with a binder. |
