PURPOSE: To acquire rare earth magnet material powder of good magnetic characteristic by acquiring recrystallization aggregate structure of R2T14B type intermetallic compound phase by performing hydrogen occlusion treatment and dehydrogenating treatment at specified treatment conditions for R-T-B alloy raw material and by cooling and grinding it thereafter.
CONSTITUTION: Hydrogen occlusion treatment is performed for R-T-B alloy raw material to accelerate phase transformation by raising a temperature from a room temperature up to a specified temperature within a range of 500 to 1000°C in hydrogen atmosphere or in mixture gas atmosphere of hydrogen and inert gas and keeping it thereafter. Then, rare earth magnet material power with recrystallization aggregate structure of R2T14B-type intermetallic compound phase is manufacture by performing dehydrogenating treatment for accelerating phase transformation by holding the raw material in vacuum atmosphere of 1 Torr of less at a specified temperature within a range of 500 to 1000°C and by cooling and grinding it thereafter. In this manufacturing method, a hydrogen pressure in hydrogen atmosphere in the hydrogen occlusion varies a hydrogen partial pressure in mixture gas atmosphere of hydrogen and inert gas up and down.
TAKESHITA TAKUO
NAKAYAMA RYOJI
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