| 摘要 |
PURPOSE:To prevent the deterioration of a solvent medium when a magnetic coating material is manufactured by a method wherein the physical properties of surface of powder is remodelled by conducting a prescribed surface treatment on hexagonal system ferrite magnetic powder. CONSTITUTION:Hexagonal system ferrite magnetic powder is surface-treated using tangstic acid anion and/or molybdic acid anion. WO4<2->, [W12O46]<20->, and the like, MoO4<2->, [MoO7O24]<6-> and the like are used. The larger the valence number becomes, the easier the specific attraction becomes. Magnetic powder is dispersed into the aqueous solution of tangstate or molybdate and anion is adsorbed. The surface density of the tangstic acid ions on the magnetic powder is selected to 0.1 to 10ion/nm<2>, and the surface density of molybdic acid ion is also selected in the range same as above- mentioned. This surface-treated magnetic powder is kneaded with bonding resin, and it is spread on the surface of the non-magnetic supporting member which is publicly known. According to this constitution, no deterioration is generated in a solvent medium when it is formed into a coating material, high filling adaptability and a high orientation can be obtained, and a recording medium of high output can also be obtained. |
