| 摘要 |
PURPOSE:To prevent a molded material from being cracked and to enhance the corrosion resistance by a method wherein, after a molding assistant selected from zinc stearate, magnesium stearate and calcium stearate, and a thermosetting resin have been added to rare-earth magnetic powder and have been mixed, they are compressed and molded. CONSTITUTION:After rare-earth magnetic powder, a molding assistant in the form of a stearic-acid-related lubricant and furthermore a thermosetting resin have been mixed, they are fed into a compression mold and are molded by being pressurized at a pressurization force of e.g., about 3-10 tons/cm<2>. As for the rare-earth magnetic powder, the rare-earth-cobalt-related magnetic powder or the rare-earth-iron-related magnetic powder is usable. As for the molding assistant, the powdery lubricant to be selected from zinc stearate, magnesium stearate and calcium stearate is used; in this case, it is especially desirable that the volume to be added is in the range of 0.05-5 wt. %. By this method, a molded material is hard to crack during a compression molding process or at a knockout after the process; the yield rate of a permanent magnet is enhanced sharply; the corrosion resistance is enhanced. |
