ZHOU Shouzeng ZHANG Jin MA Deqing GAO Maolin University of Science and Technology Beijing
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Beijing
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China
金属学报(英文版)
The magnetic properties,microstructure and magnetic hardening of sintered (Nd_(1-x)Dy_x)_(16)Fe_(77.2)B_(6.8) and Nd_(16)Fe_(77.2)B_(6.8)+ywt-%Dy_2O_3 magnets have been stud- ied.As an addition of Dy to the magnet during smelting,Dy atoms may enter the matrix phase Nd_2Fe_(14)B,so as to enhance H_A,refine grains and improve boundary struc- ture,as well as to increase H_(ci)of the magnet.If Dy_2O_3 is added to powder material prior to sintering,Dy atoms diffuse into the epitaxial layer of grains of matrix phase causing enhancement of K′_1,also refinement of grains and improvement of boundary structure.The NdFeB based permanent magnets with higher H_(ci) and greater(BH)_m may be produced by adding about 2—3 wt-% Dy_2O_3 which make a favourable condition for lower cost.
关键词:
NdFeB magnet
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null
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null
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null
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null
ZHOU Shouzeng TANG Weizhong WANG Run University of Science and Technology Beijing
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Beijing
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China
金属学报(英文版)
The boundary microstructure of sintered alloy Nd_(15.5)Fe_(77)B_-(7.5) has been studied by TEM,AES and SAED.The boundary structure may be distinguished into 4 types.The first three types remain the same during annealing,and the fourth changes its microstructure remarkably.The 4th type is composed of two different regions,i.e.,the central Nd-rich phase and the epitaxial laver of the Nd_2Fe_(14)B grains.Owing to the atomic diffusion and other types of mass trans- port,magnetic hardening occurred in the epitaxial layer,thus the coercivity of the alloy has been improved.
关键词:
NdFeB magnet
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null
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null
胡芳
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许伟
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代明江
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林松盛
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侯惠君
材料导报
着重概述了国内外应用于NdFeB永磁材料的物理气相沉积(PVD)技术的种类、特点及所制备防护涂层耐腐蚀性能的研究进展,总结了NdFeB永磁材料的前处理和后处理工艺的研究现状,并提出NdFeB永磁材料PVD技术及相关工艺的改进方法.
关键词:
NdFeB永磁材料
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物理气相沉积
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耐腐蚀性能
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前处理
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后处理
杨晓红
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范志康
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盛尊友
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梁淑华
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肖鹏
稀有金属材料与工程
采用座滴法分别研究在真空和氮气气氛中和不同温度条件下纯金属Sn,Zn,Bi及Sn-Zn-Bi系合金在NdFeB磁体上的润湿性.结果表明:单一元素Sn和Bi与NdFeB磁体间的润湿性不好,接触角比较大;而Zn与NdFeB磁体间的接触角为零,润湿性非常好.为了获得熔点较低、又与NdFeB磁体间润湿良好的合金,配制一定成分的Zn-Sn-Bi系合金,并测定其熔点.Zn-Sn-Bi合金中,当Bi含量增加到1.0%(质量分数, 下同)以后,随着Bi含量的增加,Sn-Zn-Bi合金与NdFeB磁体间的润湿性改善,原因是Bi减小了液态合金的表面张力,计算和实验都证实了这一点.Sn-8.5Zn-7Bi熔点为194.3 ℃,合金与NdFeB磁体间的接触角仅为53.2°.
关键词:
座滴法
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润湿性
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NdFeB磁体
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Sn-Zn-Bi合金系
周寿增
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唐伟忠
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王润
金属学报
用TEM观察了烧结NdFeB永磁合金的内边界显微结构,发现该合金存在4种类型的边界。回火前后前三类边界的形貌没有变化,而第4类边界的显微结构发生了显著的变化。用SAED和AES分析了第4类边界的成分与结构,该边界由两个区域组成,即富Nd相区和Nd_2Fe_(14)B晶粒的外延层。回火时,由于原子的扩散和物质迁移,Nd_2Fe_(14)B晶粒的外延层发生了磁硬化,因而合金的矫顽力得到提高。
关键词:
NdFeB永磁
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microstructure
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coercivity
周寿增
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张瑾
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马德青
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高茂林
金属学报
研究了(Nd_(1-x)Dy_x)_(16)Fe_(77.2)B_(6.8)和Nd_(16)Fe_(77.2)B_(6.8)+ywt-％ Dy_2O_3磁体的磁性能、显微结构和磁硬化,在冶炼时添加Dy,Dy原子进入基体相,使其H_A提高,并细化晶粒和改善边界结构,提高磁体的矫顽力H_c,在制粉时添加Dy_2O_3,Dy原子进入基体相晶粒的外延展,使其K_1~2提高,同样细化晶粒和改善边界结构,并减少外延层厚度,提高磁体的矫顽力H_(ci),添加约2—3Wt—％的Dy_2O_3可制造出高H_(ci)高磁能积(BH)_m的NdFeB系烧结永磁材料。
关键词:
NdFeB磁体
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coercivity
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microstructure
