BONDED MAGNET, ITS MANUFACTURING METHOD, AND MAGNET MATERIAL USED THEREFOR

摘要

PROBLEM TO BE SOLVED: To improve the corrosion resistance of a bonded magnet using an R-Fe-N magnet material with high reproducibility by maintaining the characteristic of the magnet material whose intrinsic corrosion resistance is high. SOLUTION: The bonded magnet is obtained by molding a mixture of the R-Fe-N (rare-earth-iron-nitrogen) magnet material and a binder component into a desired magnet shape. The magnet particles constituting the R-Fe-N magnet material maintain surface nitrogen concentrations of >=2 mass % in their areas at depths of 100 nm from their surfaces. This bonded magnet is obtained by performing a process in which the R-Fe-N magnet material is exposed to a temperature of >=80 deg.C in a nitrogen-containing atmosphere or by using an R-Fe-N magnet material having a surface nitrogen concentration which is higher than the mean nitrogen concentration of all magnet particles.