| 摘要 |
PROBLEM TO BE SOLVED: To solve the problems of a tendency that rare-earth group magnetic powders are easily oxidized, and as a particle size is reduced, magnetic characteristics are lowered by an oxidization deterioration, and risk of an ignition is increased in handling, and further rust is generated by oxidization in Nd-Fe-B magnetic powders, and improvements in rust-resistance and oxidization-resistance are conducted with tannin, ester phosphate, or the like, but they are yet insufficient. SOLUTION: The surface of rare-earth group magnetic powders is processed with a solution of pH 6 or higher containing a salt of an organic sulfonic acid, thereby obtaining magnetic powders having superior rust-resistant effect and oxidization-resistant effect. Accordingly, a post-processing for rust-resistance, oxidization-resistance, or the like by epoxy spray plating, etc., is dispensed with for a boned magnet using them. |
