| 摘要 |
PURPOSE:To provide excellent recording and reproducing characteristics and to improve corrosion resistance and durability by superposing a ferromagnetic Co-Cr alloy, Co oxide layer and prescribed fatty acid metallic salt on an arom. polyimide film. CONSTITUTION:The coefft. of thermal expansion of the arom. polyimide film 1 obtd. by adjusting the amt. of the constituting components to be used and copolymerizing the components is made approximately coincident with the coefft. of thermal expansion of a ferromagnetic material. A substrate 1 may be glass or Al. The ferromagnetic Co-Cr alloy film 2 is formed thereon by a sputtering method, then the film forming temp. can be made up to about 250 deg.C and the excellent magnetic film is easily formed. The film 2 has the excellent corrosion resistance and is the vertically magnetized film having magnetic anisotropy perpendicularly to the plane. The Co oxide layer 3 is then deposited on the layer 2 by sputtering in O2 under the prescribed pressure to prevent the adhesion of the layer 2 and the head and to improve the wear resistance. The surface thereof is coated with the fatty acid metallic salt layer 4 of the prescribed formula where n, m are integers and M is a metal. M is Ba, Pb, etc. The magnetic recording medium having high quality is obtd. by such constitution.
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