Patent ID: 9082538
Filing Date: 2015-07-14
Classification: H01F

Abstract:
1. A sintered Nd—Fe—B permanent magnet, comprising: (A) 90˜95 wt % of a master-phase alloy powder, by weight of the permanent magnet, wherein the master-phase alloy powder comprises 11˜16% of Nd, 5.4˜6.6% of B, 0˜6% of M and a balance of Fe by atomic percent, wherein M is at least one selected from the group consisting of Dy, Tb, Nb, Co, Ga, Zr, and Al; and (B) 5˜10 wt % of an intergranular-phase alloy powder, by weight of the permanent magnet, wherein the intergranular-phase alloy powder is modified by a nano-powder additive before being sintered to form the sintered Nd—Fe—B permanent magnet, the nano-powder additive is at least one selected from the group consisting of NiAl, TiC, SiC, AlN, TiN, and ZrN, the intergranular-phase alloy powder before being modified comprises 13.5˜30% of Nd, 4˜7% of B, 0˜15% of R and a balance of Fe by atomic percent, where R is at least one selected from the group consisting of Dy, Tb, Nb, Co, Ga, Zr, Cu, Al, and Si, the sintered Nd—Fe—B permanent magnet is obtained by a two-alloy method, the intergranular-phase alloy powder is modified by an amount of the nano-powder additive sufficient so that the sintered Nd—Fe—B permanent magnet has an intrinsic coercivity of about 30KOe or more, and the amount of the nano-powder additive is 0.01˜1% by weight of the intergranular-phase alloy powder.