共查询到19条相似文献,搜索用时 62 毫秒
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采用多晶材料趋近饱和定律研究了非晶Fe39.4-xCo40Si9B9Nb2.6Cux(x=O.5,1,1.5)合金在不同温度纳米晶化后的有效磁各向异性常数(K).结果表明,Cu含量较低(x=0.5)时,纳米晶粒较大并且在较低的退火温度(550℃)下析出硬磁相,(K)随退火温度Ta升高显著增加;随着Cu含量的增加,有效地细化了晶粒,并且抑制了硼化物的析出,(K)明显减小.讨论了(K)与晶粒尺寸D及初始磁导率的关系. 相似文献
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稀土合金RCo5中稀土离子的磁晶各向异性 总被引:2,自引:1,他引:1
《原子与分子物理学报》2005,22(1):165-167
利用单粒子点电荷模型研究了RCo5中一系列稀土离子,包括轻离子Pr3+,Nd3+和重离子Tb3+,Dy3+,Er3+的磁晶各向异性.计算分析表明过渡族元素对晶场的贡献和晶场高阶项不可忽略,虑及过渡族元素和晶场高阶项对晶场的贡献后,得到的各稀土离子的磁晶各向异性常数及其随温度变化都与实验一致的结果,此结果还特别解释了以前不能解释的轻稀土离子Pr3+的易锥向取向. 相似文献
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在CO2激光功率为50—300W、扫描速度为20mm/s、激光散光斑为20mm照射条件下 ,诱导非 晶Fe735Cu1Nb3Si135B9带中发生结构重组,产生定量纳米α-F e(Si)晶相形成双相组织结构材料. 利用穆斯堡尔谱研究了非晶Fe735C u1Nb3Si135B9合金激光纳米化的 超精细结构. 实验结果表明,激光诱导非晶 Fe735Cu1Nb3Si135B 9纳米化后,其超精细磁场的分布随 着激光功率变 化由单峰向双峰变化,在高功率辐照时, 出现了双峰分布,并且峰位向高场移动. 高激光 功率辐照非晶Fe735Cu1Nb3Si135 sub>B9合金纳米晶化相有四种超精细结 构,即2个超精细磁场较小的初晶相和2个超精细磁场较大的纳米晶化相. 其中超精细磁场较 大(17—25MA/m)的α-Fe(Si)相为DO3结构.
关键词:
激光
纳米晶α-Fe(Si)
735Cu1Nb< sub>3Si135B9')" href="#">非晶Fe735Cu1Nb< sub>3Si135B9
超精细结构
超精细磁场 相似文献
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Effective anisotropy and coercivity in nanocrystalline single-phase NdFeB permanent magnetic material 总被引:3,自引:0,他引:3
The effect of exchange-coupling interaction on the effective anisotropy and its varying tendency in nanocrystalline single-phase NdFeB permanent magnetic material have been investigated. The results show that the exchange-coupling interaction between grains makes the effective anisotropy of material, Keff, decrease with the reduction of grain size. The variation of Keff is basically the same as that of coercivity. The decrease in effective anisotropy is the main reason of the reduction of coercivity for nanocrystalline single-phase NdFeB permanent magnetic material. In order to get high anisotropy and coercivity in nanocrystalline single-phase NdFeB permanent material, the grain size should be larger than 35 nm. 相似文献
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Nguyen Huy Dan Pham Thi ThanhNguyen Hai Yen Nguyen Thi Thanh Huyen Duong Dinh Thang Luu Tien Hung 《Journal of magnetism and magnetic materials》2012,324(7):1435-1439
We have observed magnetic anisotropy in bulk Nd55−xCoxFe30Al10B5 (x=10, 15 and 20) alloys prepared by copper mold suction casting method with a presence of external magnetic field (quenching field) μ0H=0.25 T. By changing direction of the measuring field from perpendicular to parallel one in comparison with that of the quenching field, coercive force of the alloys slightly decreases while remanent magnetization and squareness of hysteresis loop increase more clearly. It is also found that the higher Co-concentration in the alloys the larger magnetic anisotropy is induced. The structure analyses manifest nanocrystalline particles embedded in residual amorphous matrix of the alloys. The size of the particles is in range of 10-30 nm and their crystalline phases consist of Nd2(Fe,Co)14B, Nd3Co, Nd3Al, NdAl2 and Nd. 相似文献
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S. Manjura Hoque M.A. Hakim Umasree Dhar D.K. Saha Per Nordblad D.P. Paul 《哲学杂志》2013,93(16):2117-2139
The magnetic properties of nanocrystalline Fe74Cu0.8Nb2.7Si15.5B7 alloy, which were rapidly solidified and then annealed at various temperatures between 475 and 650°C for different holding time, have been studied. Grain size, silicon content and the lattice parameter of α-Fe(Si) nanograins at the annealing temperatures were determined. Curie temperature of the amorphous phase was determined from the temperature dependence of permeability. For higher annealing temperatures and times, some Si diffused out of the α-Fe(Si) phase and formed an ordered DO3 phase of Fe3Si. This changed the overall magnetostriction and average anisotropy of the matrix, which deteriorated the magnetic softness of the material at higher annealing temperatures. Ultra-soft magnetic properties were achieved by averaging the random anisotropy via exchange interaction. Hysteresis loops for samples in as-cast and annealed conditions have also been studied. 相似文献
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The dependence of the formation of the nanocrystalline bcc-Fe phase on the alloy composition is studied for Fe80M7B12Cu1 (M: Ti, Ta, Nb, Mo) alloys. The rf-Mössbauer technique is used to determine the optimal soft magnetic properties. This technique allowed us to compare anisotropy fields in each phase present in the composite alloys. The smallest anisotropy field was found in the bcc-Fe nanograins formed in Nb- and Mo-containing alloys. 相似文献
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N. V. Ershov N. V. Dmitrieva Yu. P. Chernenkov V. A. Lukshina V. I. Fedorov A. P. Potapov 《Physics of the Solid State》2012,54(9):1817-1826
The residual lattice strains of nanocrystals, which are responsible for the formation of states with transverse magnetic anisotropy in samples of the Fe-Si-Nb-B-Cu alloys (Finemets) subjected to annealing under tensile loading with the subsequent relaxation annealing at temperatures in the range from 500 to 600°C, have been measured using X-ray diffraction. The relative extension and compression of interplanar spacings have been compared with the induced magnetic anisotropy constants determined from the magnetic hysteresis loops. It has been shown that, during the relaxation annealing at the nanocrystallization temperature (500?C540°C), the observed decrease in the residual strains is accompanied by a decrease in the transverse magnetic anisotropy constant. A linear correlation between the relative extension and compression of the interplanar spacings for different crystallographic planes and magnetic anisotropy constant has been revealed. The deviation from linearity is observed after annealing at a temperature of 600°C, which is explained by a possible increase in sizes of nanocrystals, changes in their structure, and partial crystallization of the amorphous matrix. 相似文献
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In order to better understand the problem of magnetic anisotropy in amorphous alloys produced by a rapidly quenching technique,
in-plane magnetic anisotropy of amorphous (Fe1−x
Co
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(78Si10B12 alloys was measured by means of a torque magnetometer using a disk specimen made from the amorphous alloy ribbon. The amorphous
ribbons were prepared by a single roller type quenching apparatus. It was found that the anisotropy had mostly twofold symmetry
in all the alloy cases, and that the concentrationx dependence of the anisotropy constant behaved differently from that of the magnetostriction. Moreover, the anisotropy did
not disappear by subsequent annealing at high temperatures where the internal stress relief and the crystallization were completed. 相似文献
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Mössbauer measurements have been carried out using non-polarized absorbers in order to investigate the magnetic texture in nanocrystalline Fe73.5Cu1Nb3S13.5B9 prepared from the amorphous state by crystallization. The results indicate a significant variation of magnetic domains in ribbons with the annealing temperature. Upon crystallization the component of the magnetization vector oriented parallel to the long axis of ribbons increases significantly and becomes dominant. The non-field annealing-induced magnetic texture probably arises from the shape anisotropy and intensely influences the initial magnetization process. 相似文献
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The crystal structure, crystallization, fracture behavior and mechanical properties of (Co1 ? x Fe x )89Zr7B4 (x = 0–0.7) nanocrystalline ribbons were investigated. The crystallization peaks of the amorphous ribbons tend to shift to higher temperatures with increasing Fe content. After annealing at 475°C for 3600 s, the main crystallization product is hcp-(Co,Fe) for the Co-rich composition (x = 0), bcc-(Co,Fe) for high Fe contents (x ≥ 0.3) and a mix of bcc, and fcc for intermediate compositions (0.025 ≤ x ≤ 0.15). The relative strain at fracture decreases dramatically (εf < 0.01) for x ≥ 0.15, whereas for lower Fe content it has a maximum (εf > 0.037) at x = 0.025 and 0.050 resulting in excellent resistance against fracture. The brittle ribbons (x ≥ 0.15) showed smooth fracture surface with dimples less than 230 nm in diameter, small localized or absent shear bands and large Vickers hardness (>1200 kg mm?2). On the other hand, the Co-rich ribbons with greater ductility (x = 0.025, 0.05) exhibit a vein pattern filled with voids (features ~2–11 µm), extensive shear banding and lower Vickers hardness (<1050 kg mm?2). 相似文献