RARE-EARTH-IRON-NITROGEN-BASED MAGNETIC POWDER AND METHOD FOR PRODUCING THE SAME

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PROBLEM TO BE SOLVED : To provide a rare-earth-iron-nitrogen-based magnetic powder excellent in heat resistance and magnetic properties, particularly in coercivity and magnetization, and a method for producing the same. SOLUTION : A rare-earth-iron-nitrogen-based magnetic powder includes a rare earth element R, iron Fe, and nitrogen N as main constituents, and has a crystal structure of any of a Th2Zn17 type, a Th2 Ni17 type, and a TbCu7 type and an average grain size of 1 μm or greater and 10 μm or smaller. The magnetic powder is formed, on a particle surface of the powder, with a shell layer that has the same crystal structure but is replaced 1 atom% or more and 20 atom% or less of Fe with Cr, has 10 atom% or more and 20 atom% or less of N and a thickness of 10 nm or greater and smaller than 200 nm, and is smaller than 2% of an average grain size of the powder. SELECTED DRAWING : None COPYRIGHT : (C)2018, JPO&INPIT