Ho取代对烧结NdFeB显微结构和磁体性能的影响

Influence of Ho substitution on the microstructure and properties of sintered Nd-Fe-B magnet

通过对合金铸片成分的设计和工艺的优化,在合金成分中添加价格相对便宜的稀土元素Ho,在工业生产线上批量生产35SHT烧结钕铁硼磁体。结果表明,磁体具有比较高的取向度;其显微组织致密、晶粒细小均匀,平均晶粒尺寸为5~10μm。磁体的常温典型磁性能为Br=1.182 T,Hcb=908 kA/m,Hcj=1865 kA/m,Hk=1712 kA/m,(BH)max=266 kJ/m^3。在23~100℃,其剩磁与内禀矫顽力温度系数为–0.09%/℃和–0.57%/℃。当Pc=–1时,磁体在170℃保持2 h后,其开路磁通不可逆损失仅为–1.11%左右,具备较好的温度稳定性。

Sintered Nd-Fe-B magnet with the addition of Ho was prepared and investigated. By improving the strip-casting techniques and optimizing the alloy compositions, adding relatively low-priced rare earth element Ho, 35SHT sintered Nd-Fe-B magnet was successfully manufactured on the mass-production line. The analysis showed that 35SHT sintered Nd-Fe-B magnet possessed a high alignment degree and a dense and fine-grained homogeneous microstructure with an average grain size of 5 to 10 μm. The typical magnetic properties at room temperature were Br=1.182 T,Hcb=908 kA/m, Hcj=1.865 MA/m,Hk=1.712 MA/m,(BH)max=266 kJ/m^3. In the temperature range of 23-150 ℃, the temperature coefficients of remanence and intrinsic coercivity were –0.11%/℃ and –0.54 %/℃,respectively. The magnet with Pc=–1 featues an irreversible flux loss of about –1.11 % after being exposed at 170 ℃ for 2 h, possessing excellent magnetic properties and better thermal stability.