| 摘要 |
PURPOSE: To obtain a bonded magnet higher than a sintered magnet in performance by a method wherein magnetic powder is bound into a bonded magnet by binder formed of cured furan resin. CONSTITUTION: A certain amount of furfuryl alcohol-furfural co-condensation type furan resin as binder where acidic catalyst is added is applied to 100g of isotropic Nd2 -Fe14 -B atomized magnetic powder. Atomized magnetic powder where resin is applied is introduced into a molding die and compression-molded into a body of prescribed shape, and the molded body is cured by heating. At this point, it is favorable that a small amount of acidic catalyst is added to resin, and it is suitable that 0.005 or less equivalent weight of acidic catalyst is applied to 100g of magnetic powder, wherein one equivalent weight denotes the number of grams obtained by dividing the molecular weight of acidic catalyst by the number of hydrogen atoms capable of reacting as acid. It is preferable that the weight ratio of acidic catalyst-containing furan resin (in a cured state as binder) to a bonded magnet is set less than 20% but more than 0.5%. |
