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Li L.,Beijing University of Posts and Telecommunications | Fang Y.,Control Iron and Steel Research Institute, China | Fang Y.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | Liu Y.,Beijing University of Posts and Telecommunications
2015 IEEE International Magnetics Conference, INTERMAG 2015 | Year: 2015

As the development of the information technology and intelligence of the society, wireless sensor networks have been widely applied in many fields of life and production [1-3]. In many practical engineering applications, it is often expected to be able to conduct real-time monitoring to the inner situation of some media. One ideal way to fulfill such objectives is to embed the wireless sensors inside the medium, make them scatter randomly in the components, send commands to start them to do measurements when necessary, and transfer the result to the data receive module through the wireless sensor network to analyze and process the data by computer. © 2015 IEEE.


Liu Z.,Control Iron and Steel Research Institute, China | Liu Z.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | Fang Y.,Control Iron and Steel Research Institute, China | Fang Y.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | And 8 more authors.
2015 IEEE International Magnetics Conference, INTERMAG 2015 | Year: 2015

Sm-Co magnet was attracted attention due to its high Curie temperature and superior comprehensive magnetic properties [1-5]. Different with powder metallurgy method, melt spinning is another efficient way to prepare Sm-Co magnet. The quenching speed in melt spinning is a critical factor to obtain ribbons with high magnetic properties. Recently, D.Y. Feng [6] et al. reported that intrinsic coercivity of SmCo6.8Zr0.2 ribbons increases from 1.54kOe to 13.45 kOe with the wheel speed rising from 5 m/s to 60 m/s. And the crystallographic c-axis is parallel to the ribbon plane for the ribbons melt-spun at low speeds of 5 and 15 m/s, and this c-axis orientation is weakened at higher speeds. Tetsuji Saito [7] et al. reported that Fe content has an effect on the phase composition. A small substitution of Fe for Co in the SmCo5 alloy leads to the formation of the Sm(Co, Fe)5 phase, but that the large substitution of Fe for Co results in the formation of other phases such as the Sm(Co, Fe)7 and Sm2(Co, Fe)7 phases. © 2015 IEEE.


Wu Y.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | Wu Y.,Control Iron and Steel Research Institute, China
2015 IEEE International Magnetics Conference, INTERMAG 2015 | Year: 2015

With the increasing of the sintered NdFeB magnet application, there is a great deal of the demand of Nd, consequently the price of Nd is rising. Therefore, it is necessary to produce a novel sintered NdFeB magnet at low costs. In this paper, the dual-main-phase CeNdFeB magnets were prepared. The corrosion potential of Ce is -2.48V, which is lower than that of Nd (-2.41V) [1]. But Ce is much cheaper than Nd. Thus, we compared the electrochemical corrosion behaviors of the sintered N45 and the sintered Ce-NdFeB magnet, whose magnetic properties is equivalent with the former. All experiments were performed in a standard three-electrode cell, which consists of specimens as working electrode, saturated calomel electrode (SCE) as reference, and Pt as counter electrode. The specimens were immersed in the electrolyte for approximately 30 min prior to be tested. The test electrolyte was neutral 3.5 wt% NaCl solution and tap-water, and the temperature was maintained at 25. © 2015 IEEE.


Du X.,Control Iron and Steel Research Institute, China | Du X.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | Guo Z.,Control Iron and Steel Research Institute, China | Guo Z.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | And 8 more authors.
2015 IEEE International Magnetics Conference, INTERMAG 2015 | Year: 2015

Die upsetting is an effective method to produce bulk anisotropic Nd-Fe-B magnets with nanostructure and full density [1]. A variety of experimental evidence suggests that the grain boundary a play key role in magnetic hardening [2]. Therefore, the grain boundary diffusion method is an effective way to improve the coercivity of die-upset magnet [3, 4]. However, the special role of the grain boundary after diffusion on both magnetic structure and microstructure of the die upsetting magnets is unclear and controversial. In order to obtain the excellent coercivity in the die-upset nanocrystal-line magnets, it is necessary to get better understanding on the mechanism of the enhanced coercivity. In this work, we have fabricated nanocrystalline Nd-Fe-B magnets by hot pressing and die upsetting methods with low melting point eutectic Nd-Cu alloy addition. The coercivity has been dramatically enhanced by Nd-Cu alloy addition. To investigate mechanism of the enhancement of the coercivity, we observed microstructure and the initial magnetization curve of the die upsetting magnets with different Nd-Cu addition. © 2015 IEEE.


Liu Z.,Control Iron and Steel Research Institute, China | Liu Z.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | Sun W.,Control Iron and Steel Research Institute, China | Sun W.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | And 8 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2015

Based on the simple jet milling geometric models built by SolidWorks10.0 software, the mesh of the models was developed in ICEM CFD12.0 by Triangular (Pave) and tet/hybrid (T-Grid) meshes, and then the models were analyzed by FLUENT software. The simulation was carried out by 2ddp version; the calculation method was Segregated Solver from the classic SIMPLEC algorithm. The standard k-ε turbulence model was chosen for modeling turbulence in this work. SIMPLEC algorithm was used to solve the pressure-velocity coupling. In the two dimensional simulation, the airflow velocity field in grinding chamber was investigated, and the effects of different kinds of gases with various mass fractions on the grinding velocity field were also studied. The result showed that the highest velocity appeared on the geometric intersection point of the three nozzles in the grinding chamber. This point was the most violent reaction area of the magnetic powder and formed the primary broken region. With the pressure of grinding gas increasing, the flow velocity of the bottom nozzle and the intersection point increased. In contrast, when the pressure of grinding gas from the bottom nozzle decreased, the velocity of the bottom nozzle decreased while the flow rate did not change much. And the flow rate increased when the mass fraction of grinding gas reduced; moreover, the reduction of the mass fraction led to the decrease of the initial pressure of the flow rate with the same demand of flow rate. ©, 2015, Editorial Office of Chinese Journal of Rare Metals. All right reserved.


Liu Z.,Control Iron and Steel Research Institute, China | Liu Z.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | Fang Y.,Control Iron and Steel Research Institute, China | Fang Y.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | And 8 more authors.
IEEE Transactions on Magnetics | Year: 2015

The Sm(Co0.93-x-yFexCu0.07Zry)7.8 (x = 0.245-0.27, y = 0.02, 0.025) ribbons are prepared by melt spinning at the wheel speed of 10-60 m/s. It is found that the thickness of the ribbons is inversely proportional to the wheel surface speed ranging from 10 to 60 m/s. The X-ray diffraction and transmission electron microscopy results show that the ribbons melt-spun at 25-50 m/s are composed of 1:7H phase. Magnetic measurements show that the saturation magnetization Ms locates in the range of ∼ 80 to ∼ 110 emu/g, and remanence Mr from ∼ 50 to ∼ 80 emu/g, and intrinsic coercivity Hcj from ∼ 1200 to ∼ 5000 Oe with the increase in v from 25 to 50 m/s. The optimal magnetic properties of the ribbons are Ms: ∼ 100 emu/g, Mr: ∼ 70 emu/g, Hcj: ∼ 5000 Oe for Sm(Co0.66Fe0.245Cu0.07Zr0.025)7.8 ribbons at v = 40-50 m/s. © 1965-2012 IEEE.


Huang S.-L.,Control Iron and Steel Research Institute, China | Huang S.-L.,University of Science and Technology Beijing | Huang S.-L.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | Feng H.-B.,Control Iron and Steel Research Institute, China | And 8 more authors.
Journal of Iron and Steel Research International | Year: 2015

Magnets with nominal compositions of (Nd1-x Cex)30 Febal Cu0.1 B1 (x = 0, 0.15, 0.3 and 0.4, mass %) have been fabricated by blending powder method. The remanence (Br), intrinsic coercivity (Hc) and maximum energy product (BH)max of the RE2Fe14B type magnets deteriorated when Nd was replaced by Ce. The chemical composition and crystal structure of magnet were investigated systemically. Backscattered electron (BSE) and energy dispersive spectroscopy (EDS) results revealed that Ce-rich and Ce-lean matrix grains coexisted in the magnets. The magnetic coupling mechanism among the double hard magnetic phases was discussed. Low melting point RE-Cu phase was in favor of the formation of uniform continuous grain boundary. Transmission electron microscopy (TEM) investigation showed the presence of fcc (Nd, Ce)Ox phase in the grain boundary. When the Ce content was 15% of the total amounts of all the rare earth, the maximum energy product of the sintered magnet was 359.8 kJ/m3. © 2015 Central Iron and Steel Research Institute.


Huang S.-L.,Control Iron and Steel Research Institute, China | Huang S.-L.,University of Science and Technology Beijing | Huang S.-L.,Beijing Engineering Laboratory of Advanced Metallic Magnetic Materials and Preparation Techniques | Feng H.-B.,Control Iron and Steel Research Institute, China | And 8 more authors.
AIP Advances | Year: 2014

The substitution of cerium, a more abundant rare-earth element, for sintered Nd-Fe-B magnets has drawn intense interest. In the present work, nominal composition of Ce15Nd15FebalB1 (wt. %), with cerium constitutes increased to 50% of the total rare-earth content, was used. And Ce-free Nd30FebalB1 (wt. %) was prepared by the same preparation process as comparison. The microstructure of the sintered magnets has been investigated by means of X-ray diffraction and transmission electron microscope. The results show that there are three kinds of RE-rich phases in the same magnet, i.e., fcc-(Ce,Nd)Ox (a=0.547nm), hcp-(Ce,Nd)2O3 (a=0.386nm, c=0.604nm) and bcc-(Ce,Nd)2O3 (a=1.113nm). Ors of (140)(Ce,Nd)2Fe14B// (1-21)bcc-(Ce,Nd)2O3(∼ 3°), [001](Ce,Nd)2Fe14B// [-214]bcc-(Ce,Nd)2O3; (01-1)(Ce,Nd)2Fe14B// (101)fcc- (Ce,Nd)Ox(∼ 2°), [101](Ce,Nd)2Fe14B// [12-1]fcc-(Ce,Nd)Ox were found through selected area electron diffraction (SAED) analysis. According to the analysis, it can be concluded that cerium has partly substituted for neodymium by occupying the corresponding atom sites in the Ce15Nd15FebalB1 magnet, without changing the crystal configuration. © 2014 Author(s).

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