Claims
- 1. A magnetic recording medium comprising a non-magnetic support and a magnetic recording layer coated thereon in which ferromagnetic particles are dispersed in a binder, characterized in that the ferrmagnetic particles are given a magnetic anisotropy by a magnetic annealing treatment and the direction of the magnetic anisotropy is vertical mainly to the recording surface, the ferromagnetic particles being ferrites, Fe-Co alloys and Fe-Ni alloys, and also being oval or cubic particles having a size of at most two microns and a length/width ratio of at most 2.
- 2. The magnetic recording medium of claim 1, wherein the ferrites contain Co in a proportion of 0.3 to 30%.
- 3. The magnetic recording medium of claim 1, wherein the ferrites are represented by Co.sub.x Fe.sub.(1-x).sup.++ Fe.sub.2.sup.+++ O.sub.4 (x=0.003-0.6) or Co.sub.x Fe.sub.(2-x).sup.+++ O.sub.3-x/2 (x=0.005-0.4).
- 4. The magnetic recording medium of claim 1, wherein the magnetic annealing treatment is carried out under powdered state, followed by dispersing the powder in a binder, coating and subjecting to an orientating treatment in the vertical direction to the surface.
- 5. The magnetic recording medium of claim 1, wherein the magnetic annealing treatment is carried out while applying a magnetic field vertical to the surface of the magnetic recording medium after coated and dried.
- 6. The magnetic recording medium of claim 1, wherein the magnetic annealing treatment is carried out from a temperature of 100.degree. to 300.degree. C.
- 7. The magnetic recording medium of claim 1, wherein the orientation treatment is carried out in a magnetic field in the vertical direction to the surface.
- 8. The magnetic recording medium of claim 7, wherein the magnetic field is a DC field or AC field.
- 9. The magnetic recording medium of claim 7, wherein the magnetic field has a field strength of 500 to 5000 gauss.
Priority Claims (1)
Number |
Date |
Country |
Kind |
56-67642 |
May 1981 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 375,682, filed May 6, 1982, now abandoned.
US Referenced Citations (3)
Continuations (1)
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Number |
Date |
Country |
Parent |
375682 |
May 1982 |
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