| 摘要 |
1,232,337. Magnetic recording medium. FUJI PHOTO FILM CO. Ltd. 3 Nov., 1969 [6 Nov., 1968], No. 53797/69. Heading H1H. The magnetic layer of a magnetic recording medium comprises a mixture of a ferromagnetic iron oxide powder and a ferromagnetic CrO 2 powder dispersed in a binder, the weight ratio of the powders being 1: 4 to 4: 1. The iron oxide may be γ-Fe 2 O 3 or Fe 3 O 4 and may be doped with one or more of Co, Ni, Mn, Zn and Cr. The particles may be acicular or granular. Specified binders are vinyl chloride-acetate copolymer, acrylic resin, polyurethane, epoxy-polyamide, cellulose resin or mixtures thereof. In examples, (1) γ-Fe 2 O 3 and CrO 2 or (2) Co-doped γ-Fe 2 O 3 and CrO 2 , dispersed in nitrocellulose, are coated on to polyethylene terephthalate film. |
