包小倩
,
孙绪新
,
高学绪
,
张茂才
,
董清飞
,
周寿增
金属学报
用双合金工艺在
(Nd0.75Dy0.10Tb0.15)12.69Fe79.01Co2.00Nb0.30B6.00
近正分主合金粉中添加质量分数为3%的富稀土辅合金
(Nd0.75Dy0.10Tb0.15)25.00Fe21.50Co21.50Nb4.00Ga8.00Ti5.00Al8.00B7.00粉
和3 %的Dy2O3粉, 成功制备出超高矫顽力和高热稳定性的烧结Nd-Fe-B磁体, 内禀矫顽力
Hci和最大磁能积(BH)max分别为3028 kA/m和 254 kJ/m3,
22-220 ℃剩磁和矫顽力的温度系数
分别为--0.104%℃和--0.356%℃, 260 ℃不可逆磁通损失L irr的绝对值仅为4%。微观组织分析表明:
主相Nd2Fe14B晶粒边界光滑、平直, 富Nd相连续均匀分布于主相晶粒周围; 在Nd2Fe14B晶粒
表层附近富含Dy, Dy2O3中的Dy通过扩散与富Nd相及Nd2Fe14B晶粒表层中的Nd发生置换,
从而在界面附近增强了磁各向异性. 在此基础上, 进一步提出了制备高矫顽力烧结Nd-Fe-B
磁体中Dy的理想分布示意图.
关键词:
烧结Nd-Fe-B磁体
,
binary powder blending technique
,
Dy2O3
,
coercivity
,
thermal stability
张延忠
,
年素珍
金属学报
本文报道三种新型铁基微晶合金Fe_(73)Cu_(1.2)Nb_(3.2)Si_(12.5)B_(10)(合金1),Fe_(73.1)Cu_1Nb_(1.5)Si_(1.25)B_(10)(合金2)及Fe_(73)Cu_1Zr_3C_(0.5)Si_(12.5)B_(10)(合金3),它们具有μ'_i≥5×10~4的高相对起始磁导率、Hc≤1.0A/m的低矫顽力、在相当宽频率范围内的高有效磁导率、低铁芯损耗和窄脉冲条件下的高脉冲磁导率。在f=1kHz和H_m=0.4A/m条件下,相对有效磁导率μ’_5的最佳值为16×10~4,超过了Yoshizawa报道的μ’_5=10×10~4。最佳铁损值为P_(5/50k)=57.9W/kg、P_(2/100k)=30.2W/kg和P_(3/100k)=68W/kg,也超过了Yoshizawa报道的P_(2/100k)=38.9W/kg。这些合金都具有优良的磁性稳定性;在130℃下保温216h后起始磁导率不变,合金的主晶相是Fe_(75+y)Si_(25-y)型有序固溶体,晶粒的平均直径为10～20nm。
关键词:
微晶合金
,
relative initial permeability
,
effective permeability
,
coercivity
,
core lose
HUANG Gangxiang XU Qingzhen GAO Huimin YU Shanfu HUA Hongci WANG Geya Shanghai Iron and Steel Research Institute
,
Shanghai
,
200940
,
China.Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai
,
200050
,
China.
材料科学技术（英）
The microstructures of melt-spun Nd_135- Fe_81.74B4.76 ribbons have been investigated by means of X-ray diffraction,Mossbauer spectroscopy and HREM.Experimental results show that optimal magnetic properties of the bond- ed magnet can be obtained by melt-spun alloys at wheel velocity of 24m/s,the microstructure of which was single phase Nd_2Fe_(14)B crystallites,and no other phases,such as Nd-rich,B-rich or x-Fe phase,were present.It is considered that the high intrinsic coercivity ~iH_c can be attributed to the sin- gle-domain behaviour of Nd_2Fe_(14)B crystallite phase.
关键词:
coercivity
,
null
周寿增
,
唐伟忠
,
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
,
microstructure
,
coercivity
周寿增
,
张瑾
,
马德青
,
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
,
coercivity
,
microstructure
ZHANG Yanzhong
,
NIAN Suzhen Shanghai Iron and Steel Research Institute
金属学报(英文版)
Three new Fe-based microcrystalline alloys,i.e.,Fe_(73.1)Cu_(1.2)Nb_(3.2)Si_(12 5)B_(10), Fe_(73)Cu_1Nb_(1.5)Mo_2Si_(12.5)B_(10) and Fe_(73)Cu_1Zr_3C_(0.5)Mo_Si_(12.5)B_(10),were developed with su- perior magnetic properties.e.g.,high relative initial permeability of μ_i~15×10~4,low coercivity of H_c1.0A/m,high effective permeability and low core losses in a consid- crable wide frequency range and high pulse-magnetic permeability under narrow pulse. The optimum value of relative effective permeability,μ_5~1 is 16×10~4 under condition of f=1 kHz and H_m=0.4 A/m.The optimum values of core loss reach 57.9 30.2 and 68 W/kg under condition of f=50.100.100 KHz and B_m=0.5,0.2,0.3 T,respectively. These three alloys have superior stability of magnetic properties.Initial permeability may be not changed during heating at 130℃ up to 216 h.The main crystalline phase is ordered phase Fe_((75)+y)Si_((25)-y) which is ultrafine particles of average size 10—20 nm.
关键词:
microcrystalline alloy
,
null
,
null
,
null
,
null
,
null
ZHOU Shouzeng ZHANG Jin MA Deqing GAO Maolin University of Science and Technology Beijing
,
Beijing
,
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
,
null
,
null
,
null
,
null
L.L. Liu
,
X.F. Bi
,
S.K. Gong
金属学报(英文版)
FeNi multilayer films were prepared by EB-PVD technique. A modified TG-DSCapparatus was used to measure their Curie temperatures, which were around 760°C,lower than that of pure Fe thin films. The easy magnetization axis was in-plane. Hightemperature annealing in vacuum decreased the coercivity sharply. The saturationmagnetization also changed with heat treatment. After annealing at the temperatureequal to the substrate temperature during deposition, the saturation magnetizationdecreased.
关键词:
multilayer film
,
null
,
null
,
null
,
null
