| 摘要 |
PURPOSE: To obtain a bonded magnet higher than a sintered magnet in magnetic properties by a method wherein magnetic powder is bound into a bonded magnet with binder of furan resin cured without acidic catalyst. CONSTITUTION: A mixture of magnetic powder and binder is compression- molded, and the molded body is heated to cure the binder for the formation of a bonded magnet, wherein furan resin 100Ps or more in viscosity is used as the binder. As magnetic material is liable to be corroded by acid, it is preferable that acidic catalyst is not used as curing agent for furan resin. An effective manufacturing method where furan resin is cured as required without using acidic catalyst is that furan resin is set as high in viscosity as above 100Ps, preferably above 300Ps at compression molding. It is necessary that condensation reaction is previously induced in furan resin to a certain extent before a heat curing treatment is carried out so as to set, furan resin high in viscosity. |
