Patent ID: 7169468

Claim:
A resin bonded rare earth magnet comprising: (a) a magnet body formed by compression molding a mixture of a first thermosetting resin and a rare earth-transition metal alloy powder having a particle size of between 20 and 300 microns such that the magnet body comprises powdered magnetic particles comprising the rare earth-transition metal alloy powder, said magnet body comprising a surface having depressions and projections; (b) a filling material with a particle size of between 0.1 and 15 microns selectively fixed by a second thermosetting resin to the surface of the magnet body only in the depressions so as to cause the surface of the magnet body with the filling material to be smoother than the surface of the magnet body without the filling material, the surface of the magnet body with the filling material having a surface roughness of less than 3 microns; and (c) a corrosion inhibiting coat comprising a synthetic resin covering the surface of the magnet body with first portions of the corrosion inhibiting coat in contact with the powdered magnetic particles and second portions of the corrosion inhibiting coat in contact with the filling material.