| 简介 |
PROBLEM TO BE SOLVED : To provide a production method by whiche the reduced and diffused reaction product of rare earth-transition metal is inexpensively and safely collapsed, and magnet powder of easily handleable grain sizes can stably be produced, to provide a bond magnet composition using the magnet powder, and to provide a bond magnet.
SOLUTION : In the production method for obtaining rare earth-transition metal-nitrogen-based magnet powder, by which transition metal alloy powder, rare earth oxide powder and a reducing agent for reducing the rare earth oxide are mixed, this mixture is heated and fired in a nonoxidizing atmosphere to obtain a reduced and diffused reaction product composed of a rare earth-transition metal based master alloy, next, the reaction product is collapsed, and the obtained rare earth-transition metal alloy powder with the average particle diameter of 5 to 100 μm is subjected to nitriding treatment, water is added to the reduced and diffused reaction product, and is brought into contact with the surplus reducing agent comprised in the reaction product and the surface of the rare earth-transition metal based master alloy powder, the generated hydrogen is absorbed in the rare earth-transition metal based master alloy, and, by a difference in expansion coefficients produced between an alloy phase with the hydrogen absorbed and an alloy phase other than that, and, by the conversion of the reducing agent welding the rare earth-transition metal-based master alloy in the reaction product into oxide, the reduced and diffused reaction product is collapsed.
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