Microstructure and improved properties of sintered Nd-Fe-B magnets by grain boundary diffusion of non-rare earth

作者：Chen, W.; Huang, Y. L.^*; Luo, J. M.^*; Hou, Y. H.^*; Ge, X. J.; Guan, Y. W.; Liu, Z. W.; Zhong, Z. C.; Wang, G. P.

来源：Journal of Magnetism and Magnetic Materials, 2019, 476: 134-141.

DOI：10.1016/j.jmmm.2018.12.048

• Al film
• Grain boundary diffusion
• Corrosion resistance
• RE-rich phase

Al film, which was coated in sintered Nd-Fe-B magnets prepared by magnetron sputtering, was employed for grain boundary diffusion source. Effects of the grain boundary diffusion processes (GBDP) on the microstructure evolution and properties were investigated in detail. Through grain boundary diffusion processes, the highest coercivity of 1184 kA/m and maximum energy product of 238 kJ/m(3) could be obtained, increasing by 21.8% and 3.9%, respectively, compared with the initial magnet. Meanwhile, our results showed that fine, uniform and continuous intergranular phase induced by Al diffusion, was the main reason for properties improvement, while a weak ferromagnetic phase and the vague interface between main phase and RE-rich phase should be responsible to the deterioration of coercivity when the diffused temperature exceed 600 degrees C. Besides, the corrosion resistance of Al-diffused magnets was also greatly improved, owing to the fact that the Al element could promote the electrochemical potential of RE-rich phase and the more thin, continuous intergranular phase would also narrow the corrosion channel.

• 出版日期2019-4-15
• 单位江西师范大学; 南昌航空大学; 华南理工大学; 江西理工大学