| 摘要 |
PURPOSE:To obtain a high performance sheet-type magnet with a thickness not larger than 1.0m/m by a method wherein composition composed of ferromagnetic powder and resin binder is employed. CONSTITUTION:A sheet-type magnet is formed by extruding kneaded composition composed of ferromagnetic powder and resin. The ferromagnetic powder is made of rare-earth intermetallic compound and has a powder grain size of 3-150mum. The resin binder is polyamide resin such as nylon 6, nylon 66 or nylon 12 or thermoplastic resin such as polyethylene. The compounding ratio of the resin binder to the magnetic powder is 50-15vol.%. If mass-productivity, the dimensional accuracy of the thickness and, etc., are taken into account, the resin content is preferably 40-20vol.%. If the resin content is too large, the fluidity can be improved but the magnetic performance is degraded. On the other hand, if the resin content is less than 15vol.%, the surface of the sheet is roughed and it is difficult to form a sheet having a thickness less than 1m/m. With this constitution, a sheet-type magnet having a thickness not larger than 1m/m can be manufactured and strength, magnetizing properties and magnetic performance can be improved. |
