| 摘要 |
PURPOSE:To develop a permanent magnet having superior characteristics, by subjecting an alloy prepared by incorporating specific percentages of metalloid elements such as B, Al, etc., to a rare earth-transition metal alloy principally composed of rare earth metal and Fe or Fe and Co to crushing and then to compacting and by subjecting the resulting green compact to two-time or more heat treatments at specific temp. CONSTITUTION:A powder of rare earth-transition metal alloy having a composition represented by a general expression R(T1-yMy)z (where R means one or >=2 kinds among rare earth metals including Y, T means transition metal principally composed of Fe or Fe and Co, M means a mixture of one or >=2 kinds among metalloid elements such as B, Al, etc., and the symbols (y) and (z) stand for 0.02-0.3 and 4-9, respectively) is compacted in a magnetic of nonmagnetic field, and the green compact is subjected to a repetition of heating at 400-1,200 deg.C in vacuum or in an inert-gas atmosphere and cooling twice or more. The above heat treating temp. is lowered as the process proceeds, and the cooling rate is regulated to >=20 deg.C/min. In this way, the permanent magnet having high coercive force can be obtained. |
