Rare earth sintered magnet
AssigneeTDK Corporation
InventorsYasushi Enokido, Gouichi Nishizawa, Chikara Ishizaka
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Abstract
The present invention provides a technique to improve an adhesion strength between a magnet main body and a protective film. The rare earth sintered magnet of the present invention comprises a magnet main body of a sintered body containing a rare earth element and a protective film formed on the magnet main body, wherein the ratio of a 10-point average surface roughness Rz of the magnet main body on which the protective film is formed to a mean grain size D50 in the magnet main body (Rz/D50 ratio) is kept in a range from 0.20 to 10.00, inclusive. This gives the rare earth sintered magnet which is coated with the protective film having a high adhesion strength of 100 N/m or more and exhibits high corrosion resistance.
Claims8
A rare earth sintered magnet comprising a magnet main body of a sintered body containing a rare earth element and a protective film formed on the magnet main body, characterized in that the ratio of a 10-point average surface roughness Rz of the magnet main body on which the protective film is formed to a mean grain size D50 in the magnet main body (Rz/D50 ratio) is in a range from 0.20 to 0.81 inclusive, the D50 is 2.0 to 15.0 μm, and the Rz is 1.5 to 11 μm, the rare earth sintered magnet is an R-T-B system sintered magnet, and the protective film has an adhesion strength of 100 N/m or more.
Dependencies are inferred from the claim text.