NEODYMIUM IRON BORON PERMANENT MAGNET MANUFACTURED FROM NEODYMIUM IRON BORON WASTE, AND METHOD FOR

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PROBLEM TO BE SOLVED : To provide a neodymium iron boron permanent magnet manufactured from neodymium iron boron waste; and a method for manufacturing the neodymium iron boron permanent magnet. SOLUTION : A method for manufacturing a neodymium iron boron permanent magnet according to the present invention comprises : a step for feeding a part of raw materials, including pure iron, boron-iron, neodymium iron boron waste, and rare earth fluoride into a melting container to perform the refining thereof under a vacuum condition; a step for picking up waste to discard it by a waste disposal device; a step for feeding the remaining raw material into the melting container to perform the refining thereof, and then, dropping a liquid alloy in the state of being melted after the completion of refining on a water-cooled rotary roller to form an alloy piece; and steps for performing, on the alloy piece, the actions including hydrogen pulverization, air flow pulverization/milling, compaction into a magnet body, preliminary sintering, and sintering. The neodymium iron boron permanent magnet manufactured by the above method is 3-7 μm in crystal average particle diameter. The neodymium iron boron permanent magnet includes crystal phases and crystal grain boundaries. The crystal grain boundaries are distributed around the crystal phases. The crystal phases include Pr, Nd, Mn and Co elements, and the crystal grain boundaries include Zr, Ga, Cu and F elements. There is a Laves phase including Tb and N elements between the crystal phase and the crystal grain boundary. SELECTED DRAWING : None COPYRIGHT : (C)2018, JPO&INPIT