COMPOSITE MAGNETIC MATERIAL AND METHOD FOR MANUFACTURING THE SAME

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PROBLEM TO BE SOLVED : To provide a composite magnetic material which excels in magnetic properties and is suitable as a material for magnets, and to provide a method for manufacturing the same. SOLUTION : Granulated powders made by mixing nano iron powders, multiphase powders containing a hydrogen compound of a rare earth element and an iron-containing material, and a binder are pressure-molded. The pressure molding is carried out while performing exhaust at 0.9 atmospheres or less and a temperature of ±20°C of a decomposition temperature of the binder. Heat treatment (dehydrogenation) of the obtained first molded body is performed under a reduced-pressure atmosphere at a temperature equal to or higher than a recombination temperature to form a recombination alloy containing a rare earth element and Fe from the multiphase powders, and heat treatment (nitriding) of the obtained second molded body is performed under a nitrogen atmosphere at a temperature of 200°C to 450°C to form α'Fe16N2 from the nano iron powders and a rare earth-iron-nitrogen alloy from the recombination alloy. Both heat treatments are performed by applying a strong magnetic field. A magnetic field is applied in the nitriding treatment to form α'Fe16N2, and orientation directions of easy axes of magnetization in the rare earth-iron-nitrogen alloy and α'Fe16N2 are uniformed. COPYRIGHT : (C)2013, JPO&INPIT