R-T-B sintered permanent magnet
AssigneeHitachi Metals, Ltd.
InventorsKimio Uchida, Tsunehiro Kawata
Life of this patent
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Abstract
An R—T—B sintered permanent magnet having a composition including 28-33 weight % of R, and 0.5-2 weight % of B, the balance being substantially T and inevitable impurities, wherein R is at least one rare earth element including Y, at least one heavy rare earth element selected from the group consisting of Dy, Tb and Ho being indispensable, and T is Fe or Fe and Co, the permanent magnet having a crystal structure comprising first R2T14B-type, main-phase crystal grain particles having a higher heavy rare earth element concentration than that of a crystal grain boundary phase, and second R2T14B-type, main-phase crystal grain particles having a lower heavy rare earth element concentration than that of the crystal grain boundary phase.
Claims13
An R—T—B sintered permanent magnet having a composition comprising 28-33 weight % of R, and 0.5-2 weight % of B, the balance being substantially T and inevitable impurities, wherein R consists essentially of at least one heavy rare earth element selected from the group consisting of Dy, Tb and Ho, and at least one rare earth element selected from the group consisting of Nd, Pr, La, Sm, Ce, Eu, Gd, Er, Tm, Yb, Lu and Y, and T is Fe or Fe and Co, said permanent magnet having a crystal structure comprising first R2T14B main-phase crystal grain particles having a higher heavy rare earth element concentration than that of a crystal grain boundary phase, and second R2T14B main phase-crystal grain particles having a lower heavy rare earth element concentration than that of said crystal grain boundary phase.
Dependencies are inferred from the claim text.