共查询到17条相似文献,搜索用时 265 毫秒
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YANG Jilian ZHANG Baisheng JIN Lan DING Yongfan YE Chuntang Institute of Atomic Energy Beijing ChinaYANG Yingchang SUN Hong KONG Linshu Peking University Beijing China YANG Jilian Associate Professor P.O.Box Sub Beijing China 《金属学报(英文版)》1990,3(8):145-148
The site occupancies in permanent magnetic alloy Y_2(Fe_(0.95)Al_(0.05))_(14)B has been studied bymeans of neutron diffraction.The results from profile refinement show that Al enters thetetragonal structure of Nd_2Fe_(14)B and occupies the 4c and 8j_2 sites of the space groupP4_2/mnm preferably.The relation between the site occupancies and the magnetic proper-ties is discussed preliminarily. 相似文献
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氢作用下Nd14Fe73Co6B7的相转变 总被引:2,自引:0,他引:2
利用X射线衍射、透射电子显微镜、扫描电镜及磁测量技术观察和分析了Nd_(14)Fe_(73)Co_6B_7合金于770℃吸氢后相结构组成与变化发现铸锭中的Nd_2Fe_(14)B基体吸氢后分解成约为0.1μm的NdH_2,α-Fe和Fe_2B三相混合物,脱氢后重新结合的Nd_2Fe_(14)B相尺寸约为0.3μm;铸锭中分布在基体相周围的富Nd边界相在吸氢时扩散入Nd_2Fe_(14)B基体,在脱氢过程中保留下来,均匀地分布在由若干Nd_2Fe_(14)B细小晶粒组成的晶粒团周围 相似文献
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以Nd_2Fe_(14)B为基底的稀土永磁材料具有优异的磁性能,其在工业上得到了广泛应用。研究了用稀土Gd部分取代Nd对快淬Nd_(2.28)Fe_(13.58)B_(1.14)薄带磁性能的影响。结果表明:快淬薄带主要由RE_2Fe_(14)B相组成,同时还有少量的α-Fe相,且磁体的矫顽力随着Gd含量的增加而减小,居里温度(T_c)随着Gd含量的增加而升高,说明Gd元素的添加可提高Nd_2Fe_(14)B磁体的热稳定性。这些研究将有助于RE_2Fe_(14)B永磁体的成分设计和制造。 相似文献
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根据差热分析测量的相变点和铸态样品的金相观察及微区成分分析,绘制了通过Nd_2Fe_(14)B正分点的等硼(B=5.88at.-%,Nd≤45.41at.-%)与等钕(Nd_2Fe_(14)B-Nd_(1.1)Fe_4B_4)两个三元垂直剖面相图。证明合金液相冷却时,四方结构的Nd_2Fe_(14)B和Nd_(1.1)Fe_4B_4是经包晶反应析出的,而不是固液同成分析出。 相似文献
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《金属热处理》2017,(4)
利用溶体快淬法研究了Y的添加对Pr_2Fe_(14)B合金磁性能的影响。结果表明:薄带Pr_2Fe_(14)B的最佳铜辊转速为30 m/s。Pr_(12-x)Y_xFe_(84)B_6(x=0~12)快淬薄带主要由各向异性、纳米结构的R_2Fe_(14)B相组成,其矫顽力、剩磁,剩磁比和饱和磁化强度均随着Y含量的增加而减少。Pr_(12-x)Y_xFe_(84)B_6快淬薄带的磁晶各向异性随着Y替代量的增加而降低,导致矫顽力逐渐减少,这是由于Y_2Fe_(14)B的磁晶各向异性低于Pr_2Fe_(14)B。然而,只要Y元素含量不超过4at%,Pr_(12-x)Y_xFe_(84)B_6快淬薄带的退磁化曲线的方形度较好,晶粒间交换耦合作用也比较强。 相似文献
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LIU Jian QIU Baoqin LIU Muyi XIAO Yaofu University of Science Technology Beijing Beijing China associate professor Department of Materials University of Science Technology Beijing Beijing China 《金属学报(英文版)》1993,6(6):379-382
The phase constitution and variation of Nd_(14)Fe_(73)Co_6B_7 alloy after hydriding and subsequentdehydriding treatment at 770℃ have been investigated respectively by means of X-raydiffraction,SEM,TEM and magnetic measurement techniques.The original coarse,as castgrain structure,is dissolved into α-Fe,Nd hydride and Fe_2B mixture with average dimensionof 0.1 μm,during hydriding process,and subsequently the triphase mixture recombined intofinely unique Nd_2Fe_(14)B phase with dimension of 0.3 μm by desorbing the hydrogen.It wasfound that the Nd-rich phase distributed at the boundary of as-cast grain structure diffusedinto matrix Nd_2Fe_(14)B grain during hydriding.It remains during dehydriding and distributehomogeneously around some colonies composed of fine grains of Nd_2Fe_(14)B. 相似文献
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ZHANG Ning Central Iron Steel Research Institute Ministry of Metallurgical Industry Beijing ChinaLUO Yang San Huan New Material Research Development Center Academia Sinica Beijing China 《金属学报(英文版)》1989,2(11):333-338
According to the experimental data of phase transition taken from DTA, metallography,SEM and microzone composition, two vertical sections of the ternary phase diagram (B=5.88at.-%, Nd≤45.41 at.-% andNd_2Fe_(14)BNd_(1.1)Fe_4B_4 , B≤44.56 at.-%) have been drawn indetail. It is verified that the crystallization of both Nd_2Fe_(14)B and Nd_(1.1)Fe_4B_4 phase, duringcooling from melt, would take peritectic reaction instead of solid-liquid congruent precipita-tion. 相似文献
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用透射电镜、Auger能谱,X射线和Mossbauer等方法研究了烧结NdFeB永磁材料在90℃潮湿空气中的氧化行为。结果表明,黑色氧化组织先在富Nd晶界相处形成。沿晶界深入和扩展进入基体相Nd_2Fe_(14)B晶粒,形成表面氧化层。黑色组织内富O和Nd而贫Fe。经500h氧化后,粉末组成仍以Nd_2Fe_(14)B粒子为主,余为Fe_3O_4,Nd_2O_3和少量a-Fe_2O_3,立方Fe_2O_3。经氧化的Nd_2Fe_(14)B相四方晶格内Fe原子分布发生变化,c晶位Fe原子大部分逸失,这是氧化导致材料磁化强度降低的重要原因。 相似文献
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LIN Yijian HU Jian YOU Yunlong JING Chunyong YU Quanqin Shanghai Iron Steel Research Institute Shanghai China LIN Yijian Measuring Testing Centre Shanghai Iron Steel Research Institute Shanghai China 《金属学报(英文版)》1990,3(9):185-190
The formation of borides M_3B_2 M_2B_2 and M_(23)B_6 may be carried out from the melt-quenchedFe_(70)Cr_(18)Mo_2SiB_9 during 700—1150℃ annealing.As the temperature raising,the M_2B,themajority being Fe_2B.may be gradually replaced by Cr_2B via the co-existence between Fe_2Band Cr_2B.The Cr_2B may be formed by trans formation of Fe_2B through the atomic substitu-tion and structural adjustment.The thin slice of remaining Fe_2B is sandwiched between(100)faces of(Cr,Fe)_2B as stacking fault.The M_2B_2 is virtually composed of theMo_(1+x)(Fe,Cr)_(2-x)B_2 where x(0≤x≤1)increases with the increase of temperature. 相似文献
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YANG Hongying SHEN Baogen YANG Linyuan GUO Huiqun Laboratory of Magnetics Institute of Physics Academia Sinica Beijing China 《金属学报(英文版)》1992,5(11):396-400
The Curie temperature increases but crystallization temperature decreases with the in-crease of Ga content,x,of amorphous(Fe_(1-x)Ga_x)_(77.5)Nd_4B_(18.5) alloys.The averagemagnetic moment of Fe atoms is almost a constant.By X-ray diffraction and ther-momagnetic measurements,the crystalline phases of the alloys,an unknown phase andα-(Fe,Ga)besides Fe_3 B as major one,were identified.The relationship between roomtemperature coercive field and Ga.content was also studied. 相似文献
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使用放电等离子烧结(SPS)制备致密的纳米晶交换耦合Nd_2Fe_(14)B/α-Fe永磁合金.研究烧结温度、时间、压力对合金磁性能和显微组织的影响.结果表明,随温度、压力的升高,密度增大,磁能积增加;但温度过高或时间过长,使得晶粒长大,导致矫顽力降低.在烧结压力为500 MPa,烧结温度为700 ℃保温3 min后,得到密度为7.6 g/cm~3,晶粒细小的致密块体,其磁性能为:B_r=0.81 T,H_(ci) =856 kA·m~(-1),(BH)_m =106 kJ·m~(-3),其晶粒大小约20 nm. 相似文献
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采用熔体快淬方法制备了不同辊速(v=12m/s、15m/s、20m/s)条件下的Fe_(85)Ga_(15)合金薄带样品,对薄带样品的组织结构和磁致伸缩性能进行了研究.结果表明,合金薄带的组织结构和磁致伸缩性能与快淬时的冷却速度密切相关,v=20m/s辊速条件下制备的薄带在磁场为45kA/m时,其磁致伸缩系数λ达-125×10~6,伸缩曲线尚未完全饱和.对薄带组织形貌的观察表明,薄带样品内晶粒沿薄带厚度方向呈现出取向性排列.XRD分析表明,辊速的提高可以抑制有序DO_3相的析出,α-Fe相和非对称DO_3结构的Fe_3Ga相衍射峰发生重叠并有劈裂现象.TEM分析表明,合金基体中存在着富Ga原子团簇.薄带样品大的磁致伸缩系数主要来源于样品强的形状各向异性和非平衡制备条件下合金内部的特殊晶体结构. 相似文献
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The creep fracture behavior of intermetallic compound(Fe_(60)Ni_(40))_3(V_(98)Ti_2)has been studied.The variation of dislocation substructure was observed with TEM in the process ofsteady-state creep.It is found that there exists a large amount of stacking faults,dislocationpairs and also high density dislocation networks.SEM analysis of section near fracture sur-face points out that the intergranular crack due to coalescence of small cavities is the maincreep fracture mechanism of(Fe_(60)Ni_(40))_3(V_(98)Ti_2). 相似文献