| 摘要 |
1,213,686. Magnetic recording media. GENERAL ELECTRIC CO. 14 Nov., 1968 [4 Dec., 1967], No. 54016/68. Heading H1H. A magnetic film of predetermined coercivity is made by depositing on a substrate a magnetic film of Fe, Co, Ni or an alloy thereof, less than 3000 Š thick and having a grain size less than 500 Š; contacting the film with a material reactive with the film-forming metal, and reacting at least a portion of the material with the metal at the grain boundaries to magnetically isolate the grains and raise the coercivity of the film to the predetermined value. The reactive material does not penetrate the magnetic film beyond the grain boundaries. A coercive magnetic medium (i.e. having a magnetic intensity reducible to zero by application of a negative magnetizing force) consists of such a film on a substrate with or without an intermediate layer and/or a protective outer layer. The medium may comprise 2 or more superimposed magnetic films. The reaction of the metal film may be effected by heating or annealing it in a reactive gas e.g. oxygen, or by immersing it in a reactive material. The film itself may be made by vacuum deposition on the substrate, preferably at an angle of incidence normal to the substrate. The partial oxidation of an iron film by heating it to 100-600‹ C. in air at 10<SP>-4</SP> Torr is described. Specified substrates are glass, copper, aluminium and polyimide. In one embodiment, a glass substrate is coated consecutively with copper, iron, palladium and copper. |
