Abstract：In present work, 39SH grade Nd- Fe- B sintered magnet was upgraded to 39UH grade through Dy grain boundary diffusion, and it was compared with the traditional 39UH prepared by alloying method. The coercivity of the magnet increased from 1677 to 2218kA/m, and Dy content increased from 3. 49% to 4. 09% (mass fraction), which is 16.3% lower than alloyed 39UH magnet. Dy was found to be enriched near the grain boundary, showing a totally different trait compared with the alloyed sample, in which Dy was randomly dispersed. The high temperature coercivity and coercivity coeffeciency of diffused sample were found to be better than that of alloyed sample within the temperature ranging from 23 to 180℃. In high- temperature flux loss test within the temperature ranging from 23 to 180℃, the untreated sample showed a large irreversible flux loss, while the diffused sample and the alloyed sample remained stable. Dy grain boundary diffusion largely increased the coercivity, and that made the working point was placed upon the knee point of the BH curve and thermal demagnetization was avoided.
李建 ，程星华，周磊，刘涛，喻晓军，李波，干勇. 晶界扩散Dy钕铁硼的高温磁性能研究[J]. , 2018, 25(2): 20-25.
LI Jian，CHENG Xing- hua，ZHOU Lei，LIU Tao，YU Xiao- jun，LI Bo，GAN Yong. High temperature magnetic properties of Dy grain boundary diffused Nd- Fe- B sintered magnet. , 2018, 25(2): 20-25.
2018, Vol. 25 
