| 摘要 |
PURPOSE: To obtain a bonded magnet excellent in corrosion resistance by a method wherein resin binder solution is added to compound filled into a molding die, which is compression-molded. CONSTITUTION: Compound 4 is filled into the cavity of a molding die 1, and resin binder solution is added to the compound 4, which is compressed into a molded body by an upper punch 2 and a lower punch 3. The compound 4 is composed of anisotropic magnet powder of Nd-Co-B-Ga-Fe as a main component and 2.5% by weight of polyimide resin mixed into it. The compound is filled into a molding die, and 0.5cc of 10% acetone solution of polyimide resin is added to the compound 4. The compound 4 where 10% acetone solution of polyimide resin is added is compression-molded by a pressure of 6 ton/cm<2> under a magnetic field of 15Koe. The molded body is cured by heating performed at a temperature of 150 deg.C for one hour in a vacuum and coated with an epoxy resin film as thick as 10μm. The obtained bonded magnet is pulse- magnetized by a magnetic field of 50Koe and left to stand at a temperature of 80 deg.C for 500 hours in a relative humidity of 90%. By this setup, a bonded magnet obtained as above is very small in reduction rate of open flux and excellent in corrosion resistance. |
