| 摘要 |
PURPOSE:To obtain the magnetic recording medium having the high S/N ratio by a method wherein ferromagnetic metal impalpable powder having the specific surface area of 35-70m<2>/g, saturation magnetization (deltas) of 120-160emu/g, and metal content of 75-98wt% is kneaded with a binder to form a magnetic layer. CONSTITUTION:From the point of view of stabilization of ferromagnetic metal impalpable powder and the property of surface of the magnetic layer, the favorable range of the specific surface area is 35-70m<2>/g, and 45-60m<2>/g is desirable. When deltas is less than 120emu/g, saturation flux density Bm of the magnetic layer can not enhanced and sufficient output can not be obtained. Moreover when deltas exceeds 160emu/g, concentration of magnetic powder in an applying liquid becomes to remarkable, the magnetic layer having the flat surface becomes hard to obtain, and 128-145emu/g is desirable. When metal content is less than 75wt%, although stability can be obtained, while sufficient deltas can not be obtained, and the high output magnetic layer can not be obtained. Moreover when the content exceeds 98wt%, the layer becomes unstable, and 80-93wt% is desirable. |
