Abstract High coercivity metallic magnetic material in finely divided particle form is milled with a lubricant to convert it to a leafing flake. The flakes thus obtained are mixed with a suitable binder vehicle and solvent and coated on a non-magnetic substrate to form a leafed coating in which most of the magnetic flakes float to the surface of the vehicle to form a relatively continuous thin layer of high coercivity magnetic material. When the binder vehicle is dried or cured it firmly adheres the thin layer of magnetic material to the substrate and also provides adhesion between the flakes of magnetic material to thus provide a wear and corrosion resistant magnetic recording media capable of high resolution recording.
Magnetic recording media consisting essentially of: a non-magnetic substrate; a non-magnetic binder vehicle adherently coated upon said substrate; and a relatively continuous layer of metallic magnetic particles, said layer of particles being about 0.005 to 3 microns thick and having a coercivity greater than 250 oersteds, said layer of metallic magnetic particles being supported in and upon said binder vehicle with said binder vehicle serving to join said particles together, said magnetic particles being formed of flakes, said flakes being about 0.01 to 5 microns in diameter, about 0.001 to 1 micron in thickness, and having on their surfaces a leafing lubricant film, said leafing lubricant being of different composition than said non-magnetic binder.
Claim 2
Dependent Claim
26 words
The magnetic recording media of claim 2 wherein the magnetic particles are about 0.01 to 1 micron in diameter and about 0.01 to 0.2 micron thick.
Claim 3
Dependent Claim
22 words
The magnetic recording media of claim 2 wherein the magnetic particles are cobalt-phosphorous produced by chemical reduction from an aqueous cobalt bath.
Claim 4
Dependent Claim
22 words
The magnetic recording media of claim 2 wherein the binder vehicle is selected from the group consisting of polyurethane and epoxy polymers.