WANG Ruikun SUN Lihong LI Dongpei YING Qiming T.Takeyama General Research Institute for Non-Ferrous Metals
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Beijing
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China [Originally published in ACTA METALL SIN (CHINESE EDN) 24 (5) 1988 pp B353—B358
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received 6 May 1987
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in revised form 6 February 1988] T.Takeyama is an emeritus professor of HOKKAIDO University
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Japan
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and now is a technical adviser of GRINFM
金属学报(英文版)
The magnetic domain structure and related magnetic properties of (NdPr)_(16)Fe_(76)B_8 permanent magnet have been studied by colloid-SEM method.In thermally demagnetized state,the ma- trix grains in the magnet generally exhibit multidomain structure,i.e.,180° plate-like indi- vidual domain and a few spike-like or maze-like domains.The average width of the domain measured was 1.5μm.Grain size of single-domain was observed to be generally about 1μm and only a few up to 3μm.The results calculated are:the domain wall energy γ=36 MJ/m~2,the exchange constant A=4.5×10~(-11)J/m,the domain wall width δ=15.7nm, and the critical grain diameter of single-domain D_c=0.5μm.The dependence of high magnet- ic field gradient at grain boundaries in different magnetization directions in the adjacent mag- netic domains located on both sides of grain boundaries and the effect of microstructure on the values of K,A and δ were discussed.
关键词:
Nd-Fe-B permanent magnet
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null
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null
王瑞坤
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孙丽虹
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李东培
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应启明
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竹山太郎
金属学报
在热退磁状态,这种永磁体的基体晶粒一般为多畴结构,单个畴为180°片状畴,也有少量钉形畴和迷宫畴。测得平均畴宽为1.5μm。还观察到一些直径1μm左右的单畴晶粒和极个别直径3μm左右的单畴晶粒,计算出畴壁能γ=36mJ/m~2,交换常数A=4.5×10~(-11)J/m,畴壁厚度δ=15.7nm,临界单畴晶粒直径D_c=0.5μm。还讨论了晶界附近存在高磁场梯度与晶界两侧相邻磁畴内磁化方向的关系和微观组织对K,A和δ值的影响。
关键词:
Nd-Fe-B永磁体
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domain structure
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magnetic property
