Sintered permanent magnet

PROBLEM TO BE SOLVED : To improve the corrosion-resistance of a R-Fe-B sintered permanent magnet, while maintaining high magnetic characteristics. SOLUTION : R (R is at least one kind of rare earth elements including Y) is 27.0-31.0 wt.% B is 0.5-2.0 wt.%, N is 0.02-0.15 wt.% O is 0.25 wt.% or less, C is 0.15 wt.% or less, with remaining part being Fe. An R-Fe-b quenched alloy for the sintered permanent magnet which comprises two-phase composition corresponding to substantially a main phase and R-rich phase of the permanent magnet is used for manufacture.