RARE EARTH-IRON-NITROGEN BASED MAGNET POWDER, AND ITS PRODUCTION METHOD

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PROBLEM TO BE SOLVED : To provide rare earth-iron-nitrogen based magnet powder having excellent magnetic properties by being uniformly nitrided, thus reducing a nonmagnetic phase, and reducing the strain of crystals and the remaining of α-Fe to form into the nuclei of magnetization reversal, and to provide a method for inexpensively producing the same by a reduction diffusion process. SOLUTION : The method comprises : a stage where rare earth oxide powder, iron powder, and reducer powder selected from alkali metals or the like are mixed in a prescribed ratio; a stage where the mixture is heated at 900 to 1, 180°C in an inert gas atmosphere; a stage where the obtained reaction product is successively cooled at ≤500°C, thereafter, the inert gas is exhausted, and hydrogen is absorbed, so as to collapse the reaction product; a stage where, while the collapsed reaction product is held to ≤300°C, a powdery mixture comprising ammonia and hydrogen is fed thereto, the temperature is raised in the air flow, and the reaction product is subjected to nitriding treatment at 350 to 500°C; a stage where the same is next poured into water, so as to be subjected to wet treatment; and a stage where the obtained magnet crude powder is charged to a pulverizer, so as to be pulverized. COPYRIGHT : (C)2007, JPO&INPIT