用LZK—12A型快淬炉制备Nd12Fe77B6Co5粘结永磁

本文主要介绍用ＬＺＫ－１２Ａ型快淬炉制取Ｎｄ１２Ｆｅ７７Ｂ６Ｃｏ５永磁合金快淬磁粉的试验和合金磁粉热处理工艺与磁性能关系的研究。     

铌对纳米晶Nd2Fe14B合金组织结构与磁性能的影响

采用熔体快淬及晶化退火工艺制备了单相Nd2Fe14B纳米晶合金。研究了添加Nb对Nd12.3Fe81.7-xNbxB6.0(x=0.5,1.0,1.5,2.0,2.5,3.0)系列合金的微观组织、磁性能和晶化行为的影响规律。结果表明:添加Nb可提高晶化温度并稳定非晶相;在退火晶化过程中,加入Nb后形成的析出相可以抑制晶粒长大,使晶粒细化且分布均匀,进而提高了材料的综合磁性能。通过对系列合金磁性能分析可知:Nd12.3Fe81.2Nb0.5B6.0合金在600℃退火处理10min后的磁性能最佳,磁能积(BH)m=141.13kJ.m-3,矫顽力Hci=867.95kA.m-1,剩磁Jr=1.02T。     

Texture of Nanocomposite Nd2Fe14B／α-Fe Melt Spun Ribbons

Inrecentyears ,Nd2 Fe14 B/αFenanocompositemagnetshaveattractedconsiderableinterestbecauseoftheirfavorablelowcostandhighpotentialenergyprod ucts.However ,thehighestmaximumenergyproduct(BH) maxobtainedinlaboratoryisonly 1 85kJ·m- 3tillnow[1] ,whichisfarlowerthanthetheoreticvalue ,80 0kJ·m- 3[2 ] .Severalexchangingcouplingmod els[3,4 ] predictedthatfurtherincreaseof (BH ) maxshouldcomefromtheimprovementofmicrostructure ,suchasfinergrains ,morehomogeneousphasedistri butionandpreferentiallyo…     

提高烧结Nd—Fe—B永磁性能的途径

本文从分析影响烧结Ｎｄ－Ｆｅ－Ｂ永磁性能的因素出发，提出生产高性能烧结Ｎｄ－Ｆｅ－Ｂ永磁的途径。从而可稳定生产Ｎ４０以上高档烧结Ｎｄ－Ｆｅ－Ｂ永磁产品。     

纳米晶稀土永磁材料的制备技术研究进展

介绍了纳米晶NdFeB基、PrFeB基、SmFeN基和SmCo基稀土永磁材料的制备技术及其进展,主要包括:熔体快淬法、机械合金化法、HDDR法、磁控溅射法和热变形法等。     

非晶Pr8Fe86B6合金的晶化动力学

用差热分析（DTA），结合X射线衍射（XRD）研究了非晶Pr8Fe86B6合金的晶化动力学。结果表明：该非晶Pr8Fe86B6合金的晶化相为α－Fe固溶体和Pr2Fe14B金属间化合物，通过对两相晶化激活能的分析得出：α－Fe相的激活能在晶化初期变化不大，当其体积分散大于8％时，其晶化激活能开始减小，而Pr2Fe14B相的激活能随其体体积分数的增加而减小，且α－Fe相较Pr2Fe14B相容易易化析出。     

稀土永磁体的应用简况

本文介绍了稀土永磁（特别是Ｎｄ－Ｆｅ－Ｂ）在某些领域的应用状况。     

稀土永磁体的新应用

介绍了稀土永磁体在电机、减振器、磁选机、研磨、生产传输线等方面的最新应用趋势。     

钕铁硼永磁材料防护镀层

比较系统地研究了钕铁硼永磁材料的单层镍、双层镍、暗镍－铜－亮镍、镍铁－亮镍镀层的厚度对孔隙率及耐蚀性的影响。实验发现,在相同厚度的镀层中,暗镍－铜－亮镍镀层体系的孔隙率低,对基体防护作用强,装饰效果好。该镀层体系的试样已通过１２０ｈ的中性盐雾试验。     

磨削加工对圆柱钕铁硼永磁合金退磁曲线隆起度的影响

发现圆柱钕铁硼永磁合金经过磨削加工后，其内禀退磁曲线隆起度降低，从而也降低了磁能积。通过实验证明，隆起度降低是磨削加工应力所致，适宜的磨削工艺和热处理则可减少和消除其影响。     

低氧速凝工艺制备RE(Nd,Pr)-Fe-B稀土永磁母合金的研究

选用Nd-Pr,Fe-B合金,纯铁以及海绵锆为原料,按一定的比例,采用低氧(真空、Ar气)速凝工艺,在1400℃～1450℃,φ600mm×500mm规格铜轮,v=1m/s～2m/s的冷却强度下,制备厚度为0.2mm～0.45mm的(Nd,Pr)-Fe-B稀土永磁母合金薄片,并对产物通过XRD,SEM进行表征.采用一定工艺将合金制备成烧结永磁体,通过对退磁曲线分析,证明可获得性能理想的(Nd,Pr)-Fe-B产品.     

纳米晶Fe_3B/Nd_2Fe_(14)B粘结永磁体的磁性能研究

本文研究了粘结剂含量和温度－时间变化对纳米晶Ｆｅ３Ｂ／Ｎｄ２Ｆｅ１４Ｂ粘结永磁材料的磁性能影响。结果表明降低粘结剂含量可显著地提高纳米晶Ｆｅ３Ｂ／Ｎｄ２Ｆｅ１４Ｂ粘结永磁的磁性能；环境温度对纳米晶Ｆｅ３Ｂ／Ｎｄ２Ｆｅ１４Ｂ粘结永磁的磁性能具有重要影响，在较高的温度下其磁性能将显著下降，因此纳米晶Ｆｅ３Ｂ／Ｎｄ２Ｆｅ１４Ｂ粘结永磁只能在较低的温度环境下使用     

Effects of Alloying Elements on Microstructure and Magnetic Anisotropy of the HDDR Powder ofNd-Fe-B Alloy

ＥｆｅｃｔｓｏｆＡｌｏｙｉｎｇＥｌｅｍｅｎｔｓｏｎＭｉｃｒｏｓｔｒｕｃｔｕｒｅａｎｄＭａｇｎｅｔｉｃＡｎｉｓｏｔｒｏｐｙｏｆｔｈｅＨＤＤＲＰｏｗｄｅｒｏｆＮｄＦｅＢＡｌｏｙＧａｏＪｉａｎｒｏｎｇ（高建荣），ＳｏｎｇＸｉａｏｐｉｎｇ（宋晓平），Ｗａ...     

Preparing Process of Cerium Acetate and Rare Earth Acetate

Preparing process was presented and the influences of concentration of acetic acid, reaction temperature, the ratio of cerium carbonate and acetic acid, heat preservation time to the yield of cerium acetate were discussed.The crystalline cerium acetate and rare earth acetate such as ( La, Ce, Pr, Nd) (Ac) 3, ( Ce, Pr, Nd) (Ac) 3, ( Pr, Nd, Er,Y) (Ac) 3 and yttrium acetate were prepared under this condition.The shape, structure and composition of the crystals were determined by the methods of SEM, TG-DTA, X-ray diffraction and chemical analysis.The optimum prepared conditions of cerium acetate were described.This prepared process has characteristics such as simple process route, low cost, high yield, good quality, no pollution to environment, etc.     

Effect of Post Annealing on the Microstructure and Magnetic Properties of NdFeB/α-Fe/NdFeB Thin Films

A series of nanocomposite thin films, composed of Nd2Fe14B and α-Fe, has been prepared by DC-magnetron sputtering combined ion beam sputtering onto Si (100) substrates. The effects of post annealing on the microstructure and magnetic properties of [NdFeB/α-Fe/NdFeB]-type thin films have been investigated. The X-ray diffraction (XRD) study showed that annealing of the films for 30min at temperatures 550,600,650,700℃ resulted in the appearance of diffraction peaks, characteristic for Nd2Fe14B tetragonal structure, α-Fe and Nd2O3 phases. The investigation using the Vibrating Sample Magnetometer (VSM) with a maximum applied field of 2 T indicated that with the increase of the annealing temperature, the magnetic properties of the multilayer films were improved and reached peak value at 650℃ (Hci=41.72kA·m-1, Mr/Ms=0.4, (BH)max=30.35kJ·m-3), after which the magnetic properties were decreased greatly. Along with the increase of the thickness of α-Fe layer from Tα-Fe16nm, the coercivity Hci, saturation magnetization Ms, and remanence ratio Mr/Ms all declined. As the Atomic Force Microscope (AFM) indicated, after being annealed at 650℃ for 30min, the sample was showed fine surface morphology with grain size 60nm≤dα-Fe≤80nm and 100nm≤dNdFeB≤150nm.     

铸锭组织的不均匀性对烧结Nd-Fe-B磁体的制粉工艺及磁性能的影响

研究了Nd-Fe-B铸锭中显微组织的分布情况,观察到铸锭中Nd