METHOD OF MANUFACTURING R-T-B-BASED PERMANENT MAGNET

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a bulky R-T-B-based permanent magnet having high coercive force while making as low use of rare heavy rare-earth elements as possible using HDDR magnetic powder.

SOLUTION: R-T-B-based HDDR magnet powder is prepared first which is manufactured by an HDDR method. Then R'-Al-based alloy powder is prepared which comprises R' and Al, Al being 2-65% by atom. Mixed powder is prepared by mixing R-T-B-based HDDR magnet powder and R'-Al-based alloy powder in 1/50 to 1/10 mass proportion of the R-T-B-based HDDR magnet powder and R'-Al-based alloy powder. A green compact is prepared by compacting the mixed powder. A hot compression molding is prepared by subjecting the green compact to hot compression molding at a temperature higher than a liquid phase oozing boundary temperature Tsof the R'-Al-based alloy powder (Ts: a temperature 105°C lower than a solid-phase line temperature of a selected composition of R'-Al-based alloy) and equal to or lower than 900°C.

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