METHOD FOR MANUFACTURING RARE-EARTH-IRON-NITROGEN-BASE MAGNET POWDER AND RARE-EARTH-IRON-NITROGEN-BA

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PROBLEM TO BE SOLVED : To provide a method for manufacturing rare earth-iron-nitrogen-base magnet powder which improves magnetic properties by uniformly nitriding rare earth-iron alloy powder utilizing a reduction diffusion method, and to provide the rare earth-iron-nitrogen-base magnet powder obtained thereby. SOLUTION : Regarding the method in which rare earth oxide powder, iron powder and a reducing agent for reducing the rare earth oxide are mixed, this mixture is heated and fired in a nonoxidizing atmosphere by a reduction diffusion method to obtain a reduction diffusion reaction product including a rare-earth-iron master alloy, next, the reduction diffusion reaction product is charged to a wet type treatment apparatus, is subjected to water washing, decantation and pickling so as to be collapsed, further, the reducing agent is removed from the reduction diffusion reaction product, successively, drying is performed, and thereafter, the obtained rare-earth-iron master alloy powder is subjected to nitriding treatment to obtain rare earth-iron-nitrogen-base magnet powder expressed by the following general formula (1), for example, it is characterized in that the process from the wet type treatment to the drying treatment for the reduction diffusion reaction product is performed in the nonoxidizing atmosphere consistently : RaFe(100-a-b)Nb...(1); wherein R is one or more rare-earth elements; and a and b are atomic% and satisfy 4≤a≤18 and 10≤b≤17, respectively. COPYRIGHT : (C)2012, JPO&INPIT