R-T-B BASED SINTERED MAGNET ALLOY CONTAINING Dy AND Tb AND ITS PRODUCTION METHOD

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PROBLEM TO BE SOLVED : To improve the magnetic properties of an Nb based rare earth magnet with a magnetostriction material subjected to scrap treatment as raw material. SOLUTION : A magnetostriction material alloy containing Tb and Dy is mixed with alloy powder at least containing Nd, Fe and B, and the mixture is sintered, thus an Nd-Fe-B based sintered magnet having excellent magnetic properties, particularly in coercive force, containing larger quantities of Tb and Dy in crystal grain boundaries, thus having reduced lowering in residual magnetic flux density is obtained. Further, excellent magnetic properties equal to those in the case where expensive Tb and Dy metals are used can be obtained by using the scrap containing Tb and Dy. The quantity of the scrap to be added in a pulverizing stage is made larger than 1 wt% for increasing the coercive force, and be made lower than 20% for preventing the lowering of sinterability. Thus, a magnet material having high industrial value can be obtained. The industrial value is extremely high by using the magnetostriction material containing Tb and Dy whose regeneration is difficult in particular. COPYRIGHT : (C)2006, JPO&NCIPI