共查询到19条相似文献,搜索用时 203 毫秒
1.
2.
由国家发展计划委员会稀土办公室提出,包头稀土研究院刘国征等人主要负责起草的国家标准GB/T13560-2000《烧结钕铁硼永磁材料》,是对GB/T13560-1992的修订。修订标准规定了烧结钕铁硼永磁材料的主要磁性能和辅助磁性能。主要磁性能包括永磁材料的剩磁(Br)、磁极化强度矫顽力(内禀矫顽力)(Hci)、磁感应强度矫顽力(HcB)、最大磁能积(BHmax);辅助磁性能包括永磁材料的相对回复磁导率(rec)、剩磁温度系数( (Br))、磁极化强度矫顽力温度系数( (Hci))和居里温度(Tc)。辅助磁性能的典型值为:( (Br))=-0.12%K、测量温度范围为298K~413K… 相似文献
3.
利用熔体快淬和晶化处理的方法制备了快淬Fe3B/Nd2Fe14B永磁材料。采用XRD,DTA,VSM等方法对合金的晶化行为和磁性能进行研究。结果表明:对于Fe3B/Nd2Fe14B熔体快淬永磁粉末,升温速率对各相的析出和分解温度有一定的影响。完全过淬的Nd4.5Fe77B18.5和Nd4Fe77Cr0.5B18.5合金熔体快淬粉在进行973K,7min晶化处理过程中,首先形成Nd2Fe23B3相,然后Nd2Fe23B3相发生分解,其产物为Fe3B/Nd2Fe14B,此后再没有发生其它的相转变。当晶化温度大于953K,保温10min后,样品的剩磁、矫顽力和最大磁能积明显提高。微量元素Cr的添加对相转变温度有影响,同时可以细化晶粒,提高矫顽力,从而改善材料的永磁性能。 相似文献
4.
5.
6.
采用SC工艺和通用的熔炼工艺制备了Sm2Co17型永磁材料。对两种工艺所制备的合金金相组织、永磁材料的磁性能进行了研究。另外,也研究了合金时效处理对永磁材料磁性能和取向度的影响。结果表明,SC工艺制备的合金获得了希望的柱状晶结构,但其制备的永磁材料磁性能却明显偏低,取向度只有通用熔炼工艺的74%;时效处理能明显提高SC工艺制备的永磁材料的磁性能,且其磁性能与通用熔炼工艺制备的永磁材料相当。 相似文献
7.
在磁路结构相同的情况下,计算了体积、形状相同,但性能不同的NdFeB永磁材料所对应的气隙相同的磁路的场强分布,并比较了它们的场强大小,分析了影响场强的因素。表明在设计磁制冷永磁磁化场时,不必一味追求高磁能积材料,要综合考虑永磁材料的磁能积、矫顽力、剩磁等性能,从而为室温磁制冷机中磁化场的建立提供选材依据。 相似文献
8.
氢化钕铁硼永磁材料的磁性能 总被引:2,自引:2,他引:0
主要论述了氢化法制备的钕铁硼永磁材料的磁性能与氢化温度,脱氢温度,氢化时间以及脱氢时间之间的关系。钕铁硼合金用真空中频感应炉熔制。合金经过均匀化热处理。合金的氧氢化物的脱氢在真空/氢气氛炉中进行。 相似文献
9.
介绍了新近出现的具有双相纳米晶结构的合成稀土永磁合金的研究结果,包括获得高剩磁和矫顽力的理论解释,磁体的制备工艺及该种合全的发展前景。讨论了实现磁体实用化及获得高能积的可能途径。 相似文献
10.
11.
Dong-Tao Zhang Peng-Fan Wang Ming Yue Wei-Qiang Liu Jiu-Xing Zhang Jennifer Anand Sundararajan You Qiang 《稀有金属(英文版)》2016,35(6):471-474
Anisotropic Mn Bi/Nd Fe B(Mn Bi contents of0 wt%, 20 wt%, 40 wt%, 60 wt%, 80 wt%, and 100 wt%)hybrid bonded magnets were prepared by molding compression using Mn Bi powders and commercial hydrogenation disproportionation desorption and recombination(HDDR) Nd Fe B powders. Magnetic measurements at room temperature show that with Mn Bi content increasing, the magnetic properties of the Mn Bi/Nd Fe B hybrid bonded magnets all decrease gradually, while the density of the hybrid magnets improves almost linearly. In a temperature range of 293–398 K, the coercivity temperature coefficient of the hybrid magnets improves gradually from-0.59 %áK~(-1)for the pure Nd Fe B bonded magnet to-0.32 %áK~(-1)for the hybrid bonded magnet with 80 wt%Mn Bi, and the pure Mn Bi bonded magnet exhibits a positive coercivity temperature coefficient of 0.61 %áK~(-1). 相似文献
12.
13.
1 INTRODUCTIONRegularstructuresinmaterialsarealwayspre paredtoimprovetheirproperties .Itiswellknownthatpowderedferromagneticmaterialscanbeorientedinastaticmagneticfield .Inrecentyearshighmag neticfieldwasappliedtoinducealignmentofparticlesinsomenonferromagneticmaterialswithanisotropicmagneticsusceptibilityinroomtemperature ,suchasparamagneticYBa2 Cu3O7ceramic[1] anddiamagneticgraphite[2 ] .Ifthematerialshavearesidualanisotropyintheirmagneticsusceptibilityatahightemperature ,theycanbetex… 相似文献
14.
磁场对Bi-Mn合金两相区中MnBi相定向排列的影响 总被引:5,自引:3,他引:5
对不同成分Bi Mn合金在液固两相区和凝固过程中加磁场 ,考察磁场的磁感应强度和加热温度对合金中MnBi相的影响。结果发现 ,MnBi相沿磁场方向定向排列并且聚合长大 ,形成规则的棒状凝固组织。Bi Mn合金中MnBi相在磁感应强度为 0 .1T的磁场中就能够明显地沿磁场方向排列 ,MnBi相定向排列因子Γ随磁感应强度的增大和加热温度的升高而提高。在相同强度的磁场中 ,含Mn 6 % (质量分数 )的合金中 ,MnBi相定向排列所需的加热温度高于含Mn 3%的合金 相似文献
15.
Keiichi Koyama Yoshifuru MitsuiEun Sang Choi Yuki IkeharaEric C. Palm Kazuo Watanabe 《Journal of Alloys and Compounds》2011,509(5):L78
Differential thermal analysis was carried out for ferromagnetic material MnBi in the temperature range 300-773 K in magnetic fields up to 45 T to investigate the effect of high magnetic fields on its decomposition process and corresponding phase diagram. The decomposition temperature Tt (MnBi → Mn1.08Bi + liquid Bi) increases from 632 K (at a zero field) to 714 K by applying a magnetic field of 45 T. Furthermore, the magnetocaloric effect of MnBi is observed in 11.5-45 T in the vicinity of 689 K, showing that a field-induced composition process occurs. The obtained results show that the equilibrium state of MnBi can be controlled by a high magnetic field. 相似文献
16.
《Intermetallics》2007,15(7):845-855
Bi–6 wt% Mn alloy is solidified under a high magnetic field and its microstructures and magnetic properties have been investigated. Microstructure results show that three kinds of morphology of MnBi phase appear in different temperature zones. In all these cases, the grains are orientated with the 〈001〉-crystal direction along the magnetic field direction and aggregated. Magnetic measurement shows a pronounced anisotropy in magnetization in directions normal and parallel to the fabrication field, resulting from this alignment. The effect of the magnetic field on the Mn1.08Bi/MnBi (paramagnetic/ferromagnetic) phase transformation has been studied and the result shows that the phase transformation temperature TC increases with the increase of the external magnetic field and under a field of 10 T, a typical increase of TC is 20 °C during heating and 22 °C during cooling. The change in the morphology and in the magnetic properties of MnBi phase is discussed from the phase transformation and the crystal structure change in magnetic field. 相似文献
17.
试验研究磁性相互作用对Bi-Mn合金中MnBi析出相磁致织构组织稳定性的影响,结果发现取向析出相晶粒间磁性相互作用不仅能够使织构组织在无磁场降温过程中稳定存在,而且能够使之在无磁场条件下重新加热至低于MnBi化合物Curie温度(居里温度,指磁性相变发生的温度)的固液两相区凝固过程中稳定存在.从磁性物理出发分析取向晶粒间磁性相互作用的特点,较好地解释了试验现象. 相似文献
18.
19.
《稀有金属(英文版)》2017,(2)
Owing to the epitaxial inducement of Au atom,Au interlayer was introduced to increase the perpendicular anisotropy and the coercivity in L1_0-FePt nanocomposite film.Micromagnetics can be used to reveal the relationship between microstructure and magnetic properties of materials,and give the information of the perpendicular anisotropy and coercivity.In this work,the effect of the Au interlayer on annealed[Fe(0.5 nm)/Pt(0.5 nm)/Au(d nm)]_(10) nanocomposite recording medium by a micromagnetic model was studied.The model contains three phases:hard magnetic phase,soft magnetic phase,and nonmagnetic phase.The calculated result shows that perpendicular orientation degree of the texture and proportion of a hard magnetic phase to the total phase in the annealed film are both enhanced by increasing Au interlayer thickness.This result can be conducive to the improvement of the perpendicular anisotropy and the coercivity of the FePt nanocomposite film in the experiments. 相似文献