METHOD FOR PRODUCING RARE EARTH ELEMENT BASED PERMANENT MAGNET HAVING COPPER PLATING FILM ON SURFACE

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[PROBLEM] To provide a method for producing a rare earth element based permanent magnet having a copper plating film on the surface thereof, which uses a novel plating solution for the electrolytic copper plating treatment and allows the formation of a copper plating film excellent in adhesiveness on the surface of a rare earth metal based permanent magnet. [MEANS FOR SOLVING PROBLEMS] A method for producing a rare earth element based permanent magnet having a copper plating film on the surface thereof, characterized in that it comprises forming a copper plating film on the surface of a rare earth element based permanent magnet, by the electrolytic copper plating treatment, using a plating solution which is adjusted to have a pH of 9.0 to 11.5 and comprises three components of (1) a Cu2+ ion, (2) a chelating agent exhibiting a chelate stability constant with a Cu2+ ion of 10.0 or more and (3) a chelating agent exhibiting a chelate stability constant with an Fe3+ ion of 16.0 or more, provided that the chelate stability constant is measured at a pH of 9.0 to 11.5.