Simultaneous increase in remanence and coercivity during grain refining of Nd-Fe-B deformed magnets  

作　　者：Fengqing Wang Kanghua Chen Juan Du Jian Zhang 

机构地区：[1]CAS Key Laboratory of Magnetic Materials and Devices,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences(CAS),Ningbo 315201,China [2]Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China [3]State Key Laboratory for Powder Metallurgy,Central South University,Changsha 410083,China [4]Institute of Materials,Shanghai University,Shanghai 200444,China

出　　处：《Journal of Rare Earths》2022年第11期1763-1771,I0004,共10页稀土学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(51901237,51901234,51771220);High-tech Tacking Project from Baotou Rare Earth Research and Development Center,Chinese Academy of Sciences(GZR 2018002);Zhejiang Provincial Natural Science Foundation(LD19E010001)。

摘　　要：To explore the feasibility of deep grain-size refinement in overcoming the problem of traditional B-Htrade-off in bulk permanent magnets,the effect of deformation temperature on the texture strength,grain refining,and magnetic properties of slow-deformed Nd-Fe-B magnets was systematically studied.As a result,strong textures with gradual grain refining from conventionally large size of D=650 nm to small nanoscale size of D=53 nm(Ddenotes the lateral size of the aligned plate-like grains)are observed as the temperature reduces from T=650℃to T=450℃.Moreover,magnetic observations show a simultaneous increase in remanence and coercivity as the grain refines from D=650 nm to D=127 nm.The increase in coercivity results from the grain size refinement as well as the smaller aspect ratio of the plate-like grains,and the increase in remanence results from the improved texture homogeneity.As compared with the D=650 nm magnets,the simultaneous increase in remanence and coercivity leads to optimum enhancements of 57%in coercivity,10%in remanence,and 25%in energy product,which demonstrate the feasibility of near-nano scale grain refinement in overcoming the traditional B-Htrade-off for improved(BH)values.The failure of higher coercivities in the D≤80 nm magnets is closely related with the defect effects of the grain boundaries.Mechanisms explaining the grain refining and texture changing behavior were also discussed.

关 键 词：NdFeB magnets Grain size Plastic deformation Texture COERCIVITY Rare earths 

分 类 号：TM273[一般工业技术—材料科学与工程]