PURPOSE: To decrease noise and to improve sensitivity, durability, etc. by forming a laminated magnetic layer consisting of a lower layer composed of magnetic metallic powder of which the specific surface area by a BET method is of a specific value or below and an upper layer composed of oxide or Co-deposited type iron oxide of which the specific surface area by a BET method is of a specific value or above on a base body.
CONSTITUTION: A lower magnetic layer consisting of dispersing magnetic alloy or metallic powder of which the specific surface area by a BET method is ≤30m2/g into a binder resin is formed by a coating method on a base body which is a polyester film, etc. An upper magnetic layer contg. magnetic oxide powder or Co-deposited type iron oxide of which the specific surface area by the BET method is ≥25m2/g is formed on the magnetic layer. The ratio between the thickness of the upper magnetic layer/the thickness of the lower magnetic layer is made ≤1.0 and the two layers are so formed as to have ≥2,000 gauss residual magnetic flux density. Even if the particle size of the magnetic powder used for the lower layer is relatively large, a noise characteristic is considerably improved and the magnetic recording medium having excellent sensitivity, transferability, etc. is obtd. by the cooperative effect with the relatively good chemical stability of the upper oxide magnetic layer.
| JPS5898841 | MAGNETIC RECORDING MEDIUM |
| JPS60263320 | MAGNETIC RECORDING MEDIUM |
KURODA KAZUHIRO
HAYAMA SHINJI
| JPS5870429A | 1983-04-26 |