DyFe薄膜晶界扩散钕铁硼磁体的结构与磁学性能  

Microstructures and Magnetic Properties of Sintered NdFeB Magnets with Diffusing DyFe Films

作　　者：平沛苑 马瑞 常瑞[1,2] 秦秀芳 范九萍 王芳[1,2] 许小红 PING Pei-yuan;MA Rui;CHANG Rui;QIN Xiu-fang;FAN Ju-ping;WANG Fang;XU Xiao-hong(School of Chemistry and Materials Science,Shanxi Normal University,Taiyuan 030032,China;Key Laboratory of Magnetic Molecules and Magnetic Information Material of Ministry of Education,Taiyuan 030032,China)

机构地区：[1]山西师范大学化学与材料科学学院,山西太原030032 [2]磁性分子与磁信息材料教育部重点实验室,山西太原030032

出　　处：《稀土》2023年第4期193-201,I0007,共10页Chinese Rare Earths

基　　金：国家自然科学基金面上项目(51971122);国家重点研发计划项目(2022YFB3505301)。

摘　　要：采用磁控溅射在磁体易磁化面上沉积3μm厚度的Dy_(x)Fe_(1-x)(x=30,50,80,100)合金薄膜层,并进行适当热处理制备晶界扩散型烧结钕铁硼磁体。当Fe含量为20%(原子分数)时,Dy_(80)Fe_(20)扩散磁体在基本不影响剩磁的情况下矫顽力能够达到15.70 kOe,接近Dy扩散磁体矫顽力,性价比更高。微观结构分析表明,重稀土元素Dy沿晶界相向磁体内部扩散的同时发生了晶格扩散,在晶粒表层生成了磁晶各向异性场更强的(Nd,Dy)_(2)Fe_(14)B硬磁壳层,因而磁体矫顽力增强。Dy扩散磁体经典核壳结构出现于100μm~300μm之间,且有效扩散深度小于500μm,而Dy_(80)Fe_(20)扩散磁体在100μm处便出现了明显的核壳且壳层可延续至500μm以上,说明Fe合金化可以有效缓解Dy在扩散磁体表面的聚集并提高有效扩散深度。在任意温度区间内,Dy_(80)Fe_(20)扩散磁体的α_(Br)、β_(Hcj)均得到不同程度的改善,磁体热稳定性增强。The 3μm-thick Dy_(x)Fe_(1-x)(x=30,50,80,100)alloy films were deposited on the easy magnetized surface of the magnet by magnetron sputtering,and the appropriate heat treatment was performed to prepare the grain boundary diffused Nd-FeB magnets.When Fe content is 20%(atomic fraction),the coercivity of Dy_(80)Fe_(20)diffused magnet increases to 15.7 kOe without any remanence reduction basically,which is close to the coercivity of Dy diffused magnet,resulting in a higher cost performance.The microstructure analysis shows that Dy diffused inside the magnet along the grain boundary and the hard mag-netic shells(Nd,Dy)_(2)Fe_(14)B with high effective anisotropy field can be formed on the grain surface by lattice diffusion simulta-neously,which leads to the enhancement in coercivity of the magnet.The classical core/shell structure of Dy diffused magnet appears between 100μm and 300μm,and the diffusion depth is less than 500μm,while the Dy_(80)Fe_(20)diffused magnet has an obvious core/shell structure at 100μm,and the shells can extend up to 500μm.It is concluded that Fe alloying can effective-ly alleviate Dy aggregation on the surface of diffused magnet and improve the effective diffusion depth.Theα_(Br)andβ_(Hcj)of Dy_(80)Fe_(20)diffused magnet have been improved in different degrees at any temperature range.It is indicated that the thermal sta-bility of the magnet has been enhanced by Dy_(80)Fe_(20)grain boundary diffusion.

关 键 词：烧结钕铁硼磁体 晶界扩散 磁性能 热稳定性 稀土永磁 

分 类 号：TM273[一般工业技术—材料科学与工程]