渗镝处理工艺参数对烧结Nd-Fe-B磁体结构与磁性能的影响

Dependence of microstructure and magnetic properties of sintered Nd-Fe-B magnets on the Dy-diffusion process parameters

应用Dy-Fe-Al合金粉末作为渗材,对于工业生产的48H烧结Nd-Fe-B磁体进行渗镝处理试验。结果表明,渗镝热处理温度、时间是影响渗镝处理磁体磁性能的重要工艺因素;在渗镝热处理之后,磁体表面区域主相晶粒表现出长大的趋势。经过在1173 K保持5 h的渗镝热处理,22.58 mm×13.78 mm×5.08 mm(长×宽×厚)48H磁体渗入的镝元素质量分数约为0.52%,其内禀矫顽力上升幅度达到564.7 kA/m,同时剩磁下降0.037 T。与基础磁体相比较,渗镝处理磁体的温度稳定性得以显著改进。

Grain boundary diffusion process experiments with Dy-Fe-Al alloy powders were conducted on mass-produced 48 H sintered Nd-Fe-B magnets.Based on the experimental results,diffusion temperature and time have marked effects on the magnetic properties of grain boundary diffusion processed magnets;Nd2 Fe14 B grains in the surface region of grain boundary diffusion processed magnets show a growth tendency.A grain boundary diffusion process at 1173 K for 5 h led to a Dy content increase of about 0.52 wt%,and produced a 564.7 kA/m intrinsic coercivity increase and a 0.037 T remanence decrease for 22.58 mm×13.78 mm×5.08 mm 48 H base magnets.Compared with that of the base magnets,the temperature stability of grain boundary diffusion processed magnets is markedly improved.