| 摘要 |
PURPOSE:To prevent decreases in magnetic characteristics and electromagnetic transducing characteristics of a metal tape when left under high temps. and humidity, and simultaneously to prevent the troubles in traveling by regulating the amt. of water-soluble metallic ions which are eluted with water from the surface of a magnetic layer to an amt. not exceeding a specified amt. CONSTITUTION:The ions of alkali metal such as sodium, alkaline earth metal such as calcium, and a metal such as iron are used as water-soluble metallic ions. The ferromagnetic metallic powder is composed of pure iron or an Fe alloy, and a nonmagnetic and nonmetallic element such as B can be incorporated in small amts. to improve the characteristics. The ferromagnetic metallic powder is kneaded with a binder, and the obtained magnetic material is coated on a nonmagnetic supporting body with an existing method to obtain the recording medium. The magnetic paint consists essentially of the ferromagnetic metallic powder, a binder, and a coating solvent, and an additive such as a dispersant can be otherwise incorporated. The amt. of water-soluble metallic ions to be eluted from the surface of the metallic layer is regulated to <=10ppm/m<2>.100ml.
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