METHOD FOR MANUFACTURING PARTICLES FOR PERMANENT MAGNET
2022-07-31
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PROBLEM TO BE SOLVED : To provide a method for manufacturing particles for permanent magnet by which particles with high magnetic characteristic can be easily obtained at a low cost.
SOLUTION : This method is used to manufacture particles for permanent magnet. A hard magnetic phase and a soft magnetic phase that are not solved mutually have a composite structure, and are made of particles with an inclusion type structure where one phase is used as a core and the other phase is used as an inclusion part including the vicinity of the core. The hard magnetic phase has R-Fe-N or R-Fe-B (R is rare earth element) composition, and the soft magnetic phase has Fe, Fe-M (M is transition metal) or Fe-N composition. The method includes a first step to form an in-oil waterdrop type micro emulsion by dripping a water solution of a transition metal nitride, a water solution of a rare-earth metal nitride, and boron chloride in a solution of a surfactant and an organic solvent; a second step to form fine particles by dripping ammonia as a particle formation agent; and a third step to reduce the particles with Ca.