PURPOSE: To prevent thermoplastic resin from oxdization and to obtain a permanent magnet with fine property by a method wherein a rare earth iron system magnet alloy, whose Curie temp. is 400°C or more, is powdered so that average particle diameter is 5W30μm and is molded by injection mold measures mixing the thermoplastic resin.
CONSTITUTION: A magnet alloy, which is R-Fe system (R is at least one sort selected from Y and a rare earth element), is selected. An alloy ingot is powdered roughly by a jaw crusher and that becomes magnet powders, whose average particle diameter are 5W30μm using a jet-mill. Surface treating of the powders is performed by silane system coupling agent etc. The magnet powders are mixed with the thermoplastic resin after surface treating and are intermingled enough in a mortar. The mixed powders are molded in warm magnetic field by means of injection mold in order to produce a permanent magnet. Thereby, the permanent magnet with fine property can be obtained.
SAKAI ISAO
INOMATA KOICHIRO
