摘要
通过晶界扩散Dy元素将烧结钕铁硼磁体的牌号从39SH提高至39UH,并与传统合金化工艺添加Dy制备的39UH磁体进行了比较研究。研究发现,经过Dy晶界扩散处理后磁体的室温矫顽力由1677kA/m增加至2218kA/m,磁体Dy的质量分数从3.49%增加至4.09%,Dy使用量比传统合金化方法制备的39UH磁体节约了16.3%。电子探针分析结果显示,扩散磁体中Dy高浓度富集在晶界附近,明显不同于Dy元素呈弥散分布的合金化样品。在室温至180℃范围内晶界扩散磁体的室温矫顽力、高温矫顽力以及矫顽力温度系数均优于合金化高重稀土对比样品。室温至180℃不同温度烘烤实验表明,未处理磁体在150℃以上开始出现大幅度不可逆磁通密度衰减,而扩散处理样品和39UH比较样品则均比较稳定。进一步研究显示,经过晶界扩散处理后大幅度提高了样品矫顽力,在开路烘烤实验过程中样品工作点仍能处于拐点以上,避免了高温热退磁。
In present work,39 SH grade Nd-Fe-B sintered magnet was upgraded to 39 UH grade through Dy grain boundary diffusion,and it was compared with the traditional 39 UH prepared by alloying method.The coercivity of the magnet increased from 1677 to 2218 kA/m,and Dy content increased from 3.49%to 4.09%（mass fraction）,which is 16.3%lower than alloyed 39 UH 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 from23 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.
作者
李建
程星华
周磊
刘涛
喻晓军
李波
干勇
LI Jian1,2 ,CHENG Xing-hua2 ,ZHOU Lei2 ,LIU Tao2 ,YU Xiao-jun2, LI Bo1, GAN Yong1(1. Central Iron and Steel Research Institute, Beijing 100081, China;2. Advanced Technology and Materials Co. Ltd., Beijing 100081, Chin)
出处
《金属功能材料》
CAS
2018年第2期20-25,共6页
Metallic Functional Materials
基金
安泰科技重大技术创新项目资助(2012JA01GGN)
关键词
烧结钕铁硼
晶界扩散
矫顽力
Dy含量
高温
Nd-Fe-B sintered magnet
grain boundary diffusion
coercivity
Dy content
high temperature
