Patent ID: 7785460
Filing Date: 2010-08-31
Classification: C25D,H01F,Y10T

Abstract:
1. A method for producing a rare earth metal-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 metal-based permanent magnet by means of a copper electroplating treatment by using a plating solution having its pH adjusted to a range from 9.0 to 11.5 and containing at least the following three components: (1) Cu 2+ ions, (2) a chelating agent having a chelate stability constant of 10.0 or higher for Cu 2+ ions at pH of 9.0 to 11.5, and (3) a chelating agent having a chelate stability constant of 16.0 or higher for Fe 3+ ions at pH of 9.0 to 11.5.