Journal articles: 'NdFeB'

1

Gouteff, P. C., L. Folks, and R. Street. "MFM study of NdFeB and NdFeB/Fe/NdFeB thin films." Journal of Magnetism and Magnetic Materials 177-181 (January 1998): 1241–42. http://dx.doi.org/10.1016/s0304-8853(97)00814-7.

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Liu, Wen Feng, Kai Zhang, and Hai Jie Zhang. "Microstructure and Magnetic Properties of C-Axis-Oriented Mo/NdFeB/Mo Films." Applied Mechanics and Materials 271-272 (December 2012): 343–46. http://dx.doi.org/10.4028/www.scientific.net/amm.271-272.343.

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Mo/NdFeB/Mo thin flms were deposited by dc-magnetron sputtering onto Si substrates, then were annealed at 650 °C for 30 min. Nanostructured Mo/NdFeB/Mo films were successfully obtained with the magnetic easy axis of NdFeB perpendicular to the film plane. It was found that the c-axis orientation depends on the NdFeB sputter power. Good c-axis orientation was obtained at 40W NdFeB sputter power. Meanwhile, Mo layer can not only induce the c-axis orientation of NdFeB, but also improve the crystallization of NdFeB grains.

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Liu, Wenfeng, Mingang Zhang, Kewei Zhang, and Yuesheng Chai. "Microstructure and Magnetic Properties of NdFeB Films through Nd Surface Diffusion Process." Advances in Condensed Matter Physics 2017 (2017): 1–5. http://dx.doi.org/10.1155/2017/4296243.

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Ta/Nd/NdFeB/Nd/Ta films were deposited by magnetron sputtering on Si (100) substrates and subsequently annealed for 30 min at 923 K in vacuum. It was found that the microstructure and magnetic properties of Ta/Nd/NdFeB/Nd/Ta films strongly depend on the NdFeB layer thickness. With NdFeB layer thickness increasing, both the grain size and the strain firstly reduce and then increase. When NdFeB layer thickness is 750 nm, the strain reaches the minimum value. Meanwhile, both the in-plane and perpendicular coercivities firstly drastically increase and then slowly decrease with NdFeB layer thickness increasing. The highest in-plane and perpendicular coercivities can be obtained at NdFeB layer thickness of 750 nm, which are 21.2 kOe and 19.5 kOe, respectively. In addition, the high remanence ratio (remanent magnetization/saturation magnetization) of 0.87 can also be achieved in Ta/Nd/NdFeB (750 nm)/Nd/Ta film.

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Ramlan, Ramlan, Dedi Setiabudidaya, A. A. A. Bama, and Muljadi. "Analysis Magnetic Properties and Corrosion Resistance of Hybrid Bonded Magnet BaFe₁₂O₁₉-NdFeB." Key Engineering Materials 855 (July 2020): 28–33. http://dx.doi.org/10.4028/www.scientific.net/kem.855.28.

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Permanent Magnets made in the form of hybrid bonded BaFe12O19 / NdFeB and with binder of Poli Vynil Alcohol (PVA) as much as 3% of the total mass in each sample. The weight ratio hybride system BaFe12O19 : NdFeB is 0 % BaFe12O19 : 100 % NdFeB ; 50% BaFe12O19 : 50 % NdFeB and 70% BaFe12O19 : 30 % NdFeB. The material preparation process was begun from mixing of raw materials using HEM for 15 minutes, then added 3% wt. of PVA. The mixed powder was formed a pellet using a hydraulic press with a force of 4 tons for 1 minute, then heated with an vacuum oven at a temperature of 110 ° C for 1 hour and the last step was magnetization using impulse magnetizer. The characterization of pellet sample was done namely measurement of bulk density, flux magnetic and hysteresis loop using VSM and then measurement of corrosion resistance of hybride bonded magnet. The characterization results show that bulk density value of sample hybride 50% BaFe12O19 – 50 % NdFeB is more larger than sample hybride 70% BaFe12O19 – 30 % NdFeB , and The highest coercivity and remanence values of 3900 Oe and 2500 Gauss respectively were achieved in samples with a composition of 50% Ba-ferrite - 50% NdFeB. The hybride bonded magnet Ba-ferrite/NdFeB has more corrosion resistance than bonded magnet 100 % NdFeB.

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Zhao, Dong, Wenli Pei, Xiaoyang Wang, Jian Zheng, Chunhong Liu, and Jianjun Wang. "Influence of a Reduction Process on the Phase Component and Magnetic Properties of NdFeB Magnetic Nanoparticles." Journal of Nanoscience and Nanotechnology 21, no. 1 (January 1, 2021): 715–19. http://dx.doi.org/10.1166/jnn.2021.18460.

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NdFeB magnetic nanoparticles with a main phase of Nd2Fe14B have successfully been synthesized. The preparation includes the following processes. First, the NdFeB intermediate was synthesized by a wet-chemical method. The NdFeB intermediate was annealed at 800 °C, which resulted in the formation of an NdFeB oxide. Then, the NdFeB oxide was reduced into NdFeB nanoparticles by a second-step reduction annealing with a CaH2 reductant. The second-step reduction annealing temperature was a key factor in preparing the NdFeB nanoparticles. A lower reduction temperature of 900 °C could not completely reduce the NdFeB oxide into Nd2Fe14B. There were some residual unreduced nonmagnetic phases in the prepared materials, which resulted in obvious decreases of coercivity. A sufficiently high second-stage reduction temperature resulted in an increased reduction, and more of the Nd2Fe14B phase could be obtained. In this work, nanoparticles with a uniform morphology and an increased Nd2Fe14B phase could be obtained at an optimum reduction temperature of 940 °C, achieving a high coercivity of 5.4 kOe.

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Sudiro, Toto, Didik Aryanto, Nenen Rusnaeni Djauhari, Citra Wara Br Sinuraya, Syahrul Humaidi, and Nanang Sudrajat. "Structure and Magnetic Properties of Spark Plasma Sintered NdFeB." Advanced Materials Research 1112 (July 2015): 27–31. http://dx.doi.org/10.4028/www.scientific.net/amr.1112.27.

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A spark plasma sintering technique was used to consolidate NdFeB compacts at four different temperatures as 750°C, 850°C, 950°C and 1030°C. The surface of specimens was polished to remove the carbon paper on the surface of NdFeB compacts by using SiC paper for up to #1500 in grit. The polished NdFeB compacts were then magnetized by using impulse magnetizer K-series. In this study, the effects of temperature on the structure and magnetic properties of NdFeB magnet were studied. The results show that depending on the fabrication temperature, the X-ray diffraction patterns of NdFeB compacts are distinct. This suggests that the structure of NdFeB compacts is changed with increase in fabrication temperature. Meanwhile, the remanance Br and energy product BH(max) of NdFeB magnets tend to decrease as fabrication temperature increase.

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Afrilinda, Eva, Dagus Resmana Djuanda, Shinta Virdhian, Martin Doloksaribu, Moch Iqbal Zaelana Muttahar, and Sri Bimo Pratomo. "Morphology of NdFeB-Type Permanent Magnet Coercivity Enhancement by Heat Treatment Process." Indonesian Journal of Chemistry 21, no. 3 (December 22, 2020): 626. http://dx.doi.org/10.22146/ijc.59096.

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To understand the morphology of the coercivity enhancement by heat treatment, a commercial sintered NdFeB-type permanent magnet is annealed, and the coercivity is measured by Permagraph. It is shown that the coercivity is increased compared to the initial. Observation by X-Ray Diffraction (XRD) analysis and Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy (SEM-EDS) is then conducted. The XRD result shows the amount of NdFeB content in the NdFeB-type permanent magnet is increased after heat treatment. The more significant amount of NdFeB content causes higher coercivity. The maximum coercivity, 19 kOe, is achieved at 850 °C of heat treatment temperature, where the NdFeB content is at the highest amount. Microstructural characterizations using SEM-EDS show that at 850 °C of heat treatment temperature, the iron (Fe) content in the grain boundaries is the lowest. It causes higher coercivity. This is due to the magnetically decoupled between NdFeB grains. The decoupling magnet of the NdFeB grains is affected by the Fe content in the grain boundaries. High-temperature heat treatment at 900 and 1050 °C led to the decomposition of NdFeB content in the grains and increased the Fe content in the grain boundaries, which resulted in a substantial reduction of magnetic coercivity.

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Ramlan, Ramlan, Balada Soerya, Amdy Fachredzy, Marzuki Naibaho, and Masno Ginting. "EFFECT OF SILICON RUBBER (SIR) IN FABRICATION OF NdFeB/BaFe12O19-BASED HYBRID MAGNET." Indonesian Physical Review 7, no. 1 (November 7, 2023): 32–38. http://dx.doi.org/10.29303/ipr.v7i1.258.

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The purpose of this study was to determine the effect of physical properties (density), magnetic properties (magnetic flux), and mechanical properties (tensile strength) of NdFeB- BaFe12O19 hybrid magnets with silicon rubber adhesive. NdFeB - BaFe12O19 permanent magnet has been made with a silicon rubber (SIR) adhesive mixture. The percentage variations of magnetic powder materials used are NdFeB: BaFe12O19 (95%: 5%) and NdFeB: BaFe12O19 (90%: 10%) mixed with a weight percentage of silicone rubber with variations of 20%, 40%, 60% and 80%. Characterization includes physical properties in the form of density where the sample with 20% SIR variation has the largest bulk density value of 3.28 g/cm3 for NdFeB: BaFe12O19 (95%: 5%) and 3.24 g/cm3 for NdFeB: BaFe12O19 (90%: 10%), and mechanical properties in the form of tensile strength where the most optimum elasticity value is at 80% silicone rubber. Meanwhile, the most optimum magnetic properties of materials are owned by material samples with variations of SIR at a concentration of 20% for sample variations of 95% NdFeB and 5% BaFe12O19, which is 602.8 Gauss.

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9

Qin, Wan Zhong, and Jie He. "The Press and Mold for Bonded NdFeB Magnet Molding." Advanced Materials Research 1004-1005 (August 2014): 1373–77. http://dx.doi.org/10.4028/www.scientific.net/amr.1004-1005.1373.

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Bonded NdFeB is a high performance composite magnetic materials which developed in recent years. Compression molding is the most important making method of bonded NdFeB magnets. The Characteristics of bonded NdFeB magnets are introduced. Based on test, research and lot production practice, the important effects of mould structure, press structure and compression molding actions on magnets’ quality are analyzed, The key techniques that controlling the quality of bonded NdFeB magnets are summarized.

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Jantarattana, P., C. Sirisathitkul, A. Hunyek, and S. Maensiri. "Electric and Magnetic Properties of Recycled NdFeB-Natural Rubber Composites." Advanced Composites Letters 20, no. 2 (March 2011): 096369351102000. http://dx.doi.org/10.1177/096369351102000203.

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Electromagnetic properties of natural rubber (NR) incorporated with recycled neodymium-iron-boron (NdFeB) powder from 0 to 120 phr by the two-roll mill technique were studied. The remanent magnetization, coercive field and logarithmic value of the electrical permittivity were linearly increased with the NdFeB loading according to the rule of mixture suggesting that interactions between NdFeB clusters were moderate. The addition of 120 phr NdFeB also increased the reflection loss of NR.

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11

Liu, Zhong Wu. "New Developments in NdFeB-Based Permanent Magnets." Key Engineering Materials 510-511 (May 2012): 1–8. http://dx.doi.org/10.4028/www.scientific.net/kem.510-511.1.

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NdFeB based alloys have been used as permanent magnets for almost thirty years. The recent researches aim at optimizing the composition, microstructure and properties, reducing cost, and developing new processes. The demand for sintered magnet is increasing. Efforts are directed towards improving properties by controlling grain boundary diffusion, minimizing the rare earth (RE) content and also improving production yield. As for bonded magnets, to enhance remanence and energy product, nanocrystalline powders are employed. High thermal stability has been realized by mixing NdFeB with hard ferrite powders. For nanocrystalline and nanocomposite NdFeB based alloys, both compositional modification and microstructural optimization have been carried out. New approaches have also been proposed to prepare NdFeB magnets with idea structure. Surfactant assisted ball milling is a good top-down method to obtain nanosized hard magnetic particles and anisotropic nanoflakes. Synthesis of NdFeB nanoparticles and NdFeB/Fe (Co) nanocomposite powders by bottom-up techniques, such as chemical reduction process and co-precipitation, has been successful very recently. To assemble nanocrystalline NdFeB powders or nanoparticles into bulk magnets, various novel consolidation processes including spark plasma sintering and high velocity press have been employed. Hot deformation can be selected as the process to achieve anisotropy in nanocrystalline magnets.

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12

Li, Li, Xiang Cheng, and Feng Shi Yin. "Study on Ultrasonic Electroforming Ni-P Coatings on NdFeB Permanent Magnet." Advanced Materials Research 535-537 (June 2012): 1275–78. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.1275.

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In order to improve the corrosion resistance of sintered NdFeB magnet, experiments are done by the new process which involves ultrasonic electroforming Ni–P alloys. The influence of ultrasonic on electroforming Ni–P alloy on NdFeB was studied by using microscope, adhesion test and NaCl solution immersion test.The results showed that the Ni–P alloy deposit on NdFeB is rough and has poor adhesion without ultrasonic agitation; However, the Ni–P alloy deposit on NdFeB with ultrasonic agitation has the following advantages: uniform and smooth deposit grains, strong adhesion and good corrosion resistance.

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Qin, Wan Zhong, Jie He, and Jia Hong Meng. "Effects of Press on Compression Molding Bonded NdFeB Magnets’ Quality." Applied Mechanics and Materials 217-219 (November 2012): 1753–56. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.1753.

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Compression molding is the most important making method of bonded NdFeB magnets. Characteristics of bonded NdFeB magnets are analyzed. Based on test, research and lot production practice, the important effects of mould structure, press structure and compression molding actions on magnets’ quality are introduced, The key techniques that controlling the quality of bonded NdFeB magnets are summarized.

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14

Fu, Yudong, Feng Yan, Xiaoshuo Zhu, Xiaoxue Feng, and Zaizai Guo. "Microstructure and magnetic properties of NdFeB/Mo multilayered films prepared by magnetron sputtering." Modern Physics Letters B 30, no. 08 (March 30, 2016): 1650126. http://dx.doi.org/10.1142/s0217984916501268.

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The paper was presented to study the microstructure and magnetic properties of Mo/[NdFeB/Mo] × 10/Mo multilayered films prepared by magnetron sputtering on Si(100) substrate. The SEM observation of microstructure showed that the specimen had fine multilayer structure and the NdFeB layers were successfully separated by Mo layers on the cross-section. The interface between the NdFeB and Mo layer disappeared after annealing. X-ray diffraction patterns of the annealed films revealed that there are a large amount of Nd2Fe[Formula: see text]B phases. The thickness of Mo layer had obvious effects on magnetic properties of the samples. When it reached 21 nm, the number and the intensity of NdFeB phase increase, and the remanent magnetization ratio Mr/Ms suddenly rise. The influences of annealing on surface morphology and microstructure of NdFeB thin films were also studied.

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Zhang, Yuanbo, Foquan Gu, Zijian Su, Shuo Liu, Corby Anderson, and Tao Jiang. "Hydrometallurgical Recovery of Rare Earth Elements from NdFeB Permanent Magnet Scrap: A Review." Metals 10, no. 6 (June 24, 2020): 841. http://dx.doi.org/10.3390/met10060841.

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NdFeB permanent magnet scrap is regarded as an important secondary resource which contains rare earth elements (REEs) such as Nd, Pr and Dy. Recovering these valuable REEs from the NdFeB permanent magnet scrap not only increases economic potential, but it also helps to reduce problems relating to disposal and the environment. Hydrometallurgical routes are considered to be the primary choice for recovering the REEs because of higher REEs recovery and its application to all types of magnet compositions. In this paper, the authors firstly reviewed the chemical and physical properties of NdFeB permanent magnet scrap, and then carried out an in-depth discussion on a variety of hydrometallurgical processes for recovering REEs from the NdFeB permanent magnet scrap. The methods mainly included selective leaching or complete leaching processes followed by precipitation, solvent extraction or ionic liquids extraction processes. Particular attention is devoted to the specific technical challenge that emerges in the hydrometallurgical recovery of REEs from NdFeB permanent magnet scrap and to the corresponding potential measures for improving REEs recovery by promoting the processing efficiency. This summarized review will be useful for researchers who are developing processes for recovering REEs from NdFeB permanent magnet scrap.

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Gurram, Kalyani, and N. Pannirselvam. "A Review on Properties of Concrete with Magnetizing Cement." IOP Conference Series: Materials Science and Engineering 1219, no. 1 (January 1, 2022): 012051. http://dx.doi.org/10.1088/1757-899x/1219/1/012051.

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Abstract The incorporation of strong magnetic powders (NdFeB) into cement mixtures has produced improved mechanical properties of cement pastes. The magnetic cement (cementitious magnet) used a simple and inexpensive cement process to form complex forms of the NdFeB magnet. Particulate NdFeB has been distributed uniformly in the cement matrix. The magnetic cement composites increased in density and compressive strength with the NdFeB concentration. Magnetization (stable up to one year) also increased with NdFeB powder but there was no improvement in coercivity. The introduction of magnetic particles into cement matrices has also been another important method in recent years to enhance the mechanical and other properties of cement-based materials. Nanoparticles (IONs) made from iron oxide (Fe2O3, Fe2O4) are among the most popular cement fillers. Cement composites mixed with IONs showed enhanced compressive strength, as well as other enhanced functions. This paper presents literature analysis of a study of magnetizing cement on concrete properties.

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Zhu, Xiaofen. "New Technology of Making NdFeB by Sintering." Insight - Material Science 1, no. 1 (August 9, 2018): 9. http://dx.doi.org/10.18282/ims.v1i1.103.

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<p>Sintered NdFeB as a third-generation rare earth permanent magnet material, has been in rapid development since 1980’s due to its broad industrial applications and high electromagnetic performance. Sintered NdFeB metal materials can easily be oxidized, so future efforts to improve their antioxidative stability are required and the study of new manufacturing technology and new technology is necessary. At present, the traditional technology of sintering NdFeB is discussed, together with the processing technology of powder preparation, hydroforming and vacuum sintering. The article focuses on the milling and forming process, including the traditional ball mill to hydrogen explosion, air grinding powder, and dry magnetic ﬁeld molding to wet pressure magnetic ﬁeld oriented molding, to prevent the production process of oxidation, thereby enhancing the electromagnetic properties and their anti-corrosion antioxidant capacity. During the NdFeB sintering process, content of oxygen is regulated to control the phase change. As a result, electromagnetic properties of sintered NdFeB obtained a qualitative leap. </p>

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Imashuku, Susumu, Kazuaki Wagatsuma, and Jun Kawai. "Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets." Microscopy and Microanalysis 22, no. 1 (January 7, 2016): 82–86. http://dx.doi.org/10.1017/s1431927615015676.

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AbstractScanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium–iron–boron (NdFeB) and samarium–cobalt (Sm–Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm–Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.

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Li, Li, Zong Wei Niu, and Jian Hua Zhang. "Investigation of Material Removal Mechanism in EDM of Sintered NdFeB Permanent Magnet." Key Engineering Materials 334-335 (March 2007): 937–40. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.937.

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Sintered NdFeB permanent magnet is widely used in many applications because of its excellent magnet property. However the report of EDM research on NdFeB magnet is not available. This paper presents a detailed investigation of the material removal mechanisms of sintered NdFeB magnet through analysis of the machining debris and the surface SEM quality. It is included three types of machining mechanisms: melting and evaporating, thermal cracking, spalling or whole grain removal.

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Qin, Wan Zhong, Jie He, and Ling Yi Yao. "Research on the Molding Technology of Bonded NdFeB Magnets." Applied Mechanics and Materials 217-219 (November 2012): 1815–18. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.1815.

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For the composite powders with different NdFeB powder content , the effects of processing parameters including injection temperature, injection pressure, holding pressure and injection velocity on the sizes and properties of injection molded bonded NdFeB magnet were investigated, and the reasons of effects were also analyzed. The results show that changes in injection parameters can influence the size, density, mechanical properties and magnetic properties of bonded NdFeB magnets, and has strong influence regularity. The injection temperature and injection pressure have the greatest impact on the performance. On the basis of research, the injection molding bonded NdFeB magnet with high performance is obtained with magnetic properties Br=0.539T, Hcb=345.37kA/m, Hci=681.02kA/m, (BH)max=47.37kJ/m3 and density 5.07g/cm3 respectively.

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Chen, Yen Ju, Chao Cheng Chang, Po Jen Hsiao, and Can Xun Chang. "Investigation on the Improvement of Magnetic Properties by Hot Deformation Processes for NdFeB Magnets." Key Engineering Materials 626 (August 2014): 317–22. http://dx.doi.org/10.4028/www.scientific.net/kem.626.317.

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Traditionally, NdFeB magnets with high remanent flux density or high energy product could only be manufactured through altering the material compounds. In recent years, studies indicated that the magnet properties of NdFeB magnets could be improved through plastic deformation. These studies pointed out that the degree of plastic deformation is a key factor to improve magnetic properties. However, there are still many other process parameters that could affect the magnetic properties either positively or negatively. In this paper, process parameters such as strain, strain rate, and temperature are studied to illustrate their influences on the magnetic properties of NdFeB magnets. The magnetic property could be greatly improved when the preferred orientation appears on the microstructure of deformed NdFeB magnets. One of the experimental results showed that the energy product value had been increased by 76.7% when the effective strain value had reached 0.65. Experimental results also showed that strain rate is a dominating factor with regard to the flow stress of material. Through a proper combination of these parameters, one can obtain NdFeB magnets with their magnetic properties greatly improved.

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Ren, Meng, Jun Li, Jian Li, Song Yang, Shouhua Zhang, and Bo Li. "Removal of non-magnetic impurities on the surface of NdFeB magnets." Journal of Physics: Conference Series 2383, no. 1 (December 1, 2022): 012120. http://dx.doi.org/10.1088/1742-6596/2383/1/012120.

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NdFeB rare earth permanent magnets are widely applied in numerous fields including consumer electronics, industrial motors and new energy vehicles. Sintered NdFeB magnets are prepared by pressing and high-temperature sintering, followed by machining into desired shapes with anisotropism and high magnetic properties. During industrial production process, the appearance of non-magnetic impurities adhering on NdFeB magnet surface is a critical problem, which takes bad influences to not only magnetic properties of NdFeB, but also the qualification rate of subsequent assembled parts. There are two forms of impurities, one is gelatinous and the other is filamentary. In this paper, non-magnetic impurities on the surface of NdFeB magnets were characterized and analyzed by FTIR, EDS and SEM, and the methods to remove impurities were studied. The results showed that gelatinous impurities are stearamide derivative, which can be dissolved by xylenes under heating conditions. Filamentous impurities are cellulose derivative that can be removed by economical sodium hydroxide-urea system instead of expensive AmimCl, without damaging magnet plating and magnetic properties.

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Radwan-Pragłowska, Natalia, Julia Radwan-Pragłowska, Karol Łysiak, Tomasz Galek, Łukasz Janus, and Dariusz Bogdał. "Commercial-Scale Modification of NdFeB Magnets under Laser-Assisted Conditions." Nanomaterials 14, no. 5 (February 27, 2024): 431. http://dx.doi.org/10.3390/nano14050431.

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Rare Earth elements (REE) such as NdFeB are commonly used to produce permanent magnets. Thanks to their superior properties, these materials are highly desirable for green energy applications such as wind power generators or electric cars. Currently, REEs are critical for the ongoing development of eco-friendly solutions in different industrial branches. The emerging issue of REE depletion has led to a need for new methods to enable the life cycle elongation, resistance to wear, and external factors improvement of NdFeB magnets. This can be achieved by advanced, nanostructured coating formation of magnet surfaces to increase their functionality and protect from humidity, pressure, temperature, and other factors. The aim of the following research was to develop a new, scalable strategy for the modification of NdFeB magnets using laser-assisted technique, also known as Laser cladding. For this purpose, four different micropowders were used to modify commercial NdFeB samples. The products were investigated for their morphology, structure, chemical composition, and crystallography. Moreover, magnetic flux density was evaluated. Our results showed that laser cladding constitutes a promising strategy for REE-based permanent magnets modification and regeneration and may help to improve durability and resistance of NdFeB components.

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Sun, R. X., Z. G. Deng, Y. F. Gou, Y. J. Li, J. Zheng, S. Y. Wang, and J. S. Wang. "Feasibility of low-cost magnetic rail designs by integrating ferrite magnets and NdFeB magnets for HTS Maglev systems." International Journal of Modern Physics B 29, no. 25n26 (October 14, 2015): 1542043. http://dx.doi.org/10.1142/s0217979215420436.

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Permanent magnet guideway (PMG) is an indispensable part of high temperature superconducting (HTS) Maglev systems. Present PMGs are made of NdFeB magnets with excellent performance and cost much. As another permanent magnet material, the ferrite magnet is weak at magnetic energy product and coercive force, but inexpensive. So, it is a possible way to integrate the ferrite and NdFeB magnets for cutting down the cost of present PMGs. In the paper, the equivalent on magnetic field intensity between ferrite magnets and NdFeB magnets was evaluated by finite element simulation. According to the calculation results, the magnetic field of the PMG integrating ferrite magnets and NdFeB magnets can be increased remarkably comparing with the pure ferrite PMG. It indicates that low-cost PMG designs by integrating the two permanent magnet materials are feasible for the practical HTS Maglev system.

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Jiang, Yonggang, Takayuki Fujita, Minoru Uehara, Yuki Iga, Taichi Hashimoto, Xiuchun Hao, Kohei Higuchi, and Kazusuke Maenaka. "Fabrication of NdFeB microstructures using a silicon molding technique for NdFeB/Ta multilayered films and NdFeB magnetic powder." Journal of Magnetism and Magnetic Materials 323, no. 21 (November 2011): 2696–700. http://dx.doi.org/10.1016/j.jmmm.2011.05.061.

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Muljadi, Priyo Sardjono, Nenen Rusnaeni Djauhari, Suprapedi, and Ramlan. "Preparation and Characterization of Hybrid Bonded Magnet Ba-Ferrite/NdFeB with Epoxy Resin." Materials Science Forum 864 (August 2016): 65–69. http://dx.doi.org/10.4028/www.scientific.net/msf.864.65.

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Hybrid bonded magnet Ba-Ferrite/NdFeB with 5% wt Epoxy Resin (ER) as polymer binder hsa been developed with variations in BaFe12O19 to NdFeB weight ratio. The variation of the BaO6Fe2O3 : Nd-Fe-B weight ratio are 90%:10%; 80%:20%; 70%:30% and 60%:40%. The magnetic particle consist of Ba-Ferrite and NdFeB were mixed until homogenize and compacted by using hydraulic press machine with 8 Tonf force to form a disc shape sample. The disc sample was dried using vacuum dryer with 10 mm bar pressure at 80°C for one hour before being magnetized using impulse magnetizer. The best %wt composition ratio of Ba-Ferrite/NdFeB is 70%/30% and 60%/40%. The hybrid bonded magnetic properties at the best %wt composition ratio are: bulk density = 4.28-4.43 g/cm3, FM = 1057-1121 Gauss, Br = 3.46-3.70 kG, Hc = 3.25-3.70 kOe, and BHmax = 1.60-1.70 MGOe.

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Cheng, WenDe. "Magnetic Remanence Prediction of NdFeB Magnets Based on a Novel Machine Learning Intelligence Approach Using a Particle Swarm Optimization Support Vector Regression." International Journal of Software Science and Computational Intelligence 6, no. 4 (October 2014): 72–81. http://dx.doi.org/10.4018/ijssci.2014100105.

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Studies have shown that the chemical compositions affecting the magnetic properties of NdFeB magnets. In order to get the right NdFeB magnets, it is advantageous to have an accurate model with which one can predict the magnetic properties with different components. In this paper, according to an experimental dataset on the magnetic remanence of NdFeB, a predicting and optimizing model using support vector regression (SVR) combined with particle swarm optimization (PSO) was developed. The estimated result of SVR agreed with the experimental data well. Test results of leave-one-out cross validation show that the mean absolute error does not exceed 0.0036, the mean absolute percentage error is solely 0.53%, and the correlation coefficient () is as high as 0.839. This implies that one can estimate an available combination of different proportion components by using support vector regression model to get suitable magnetic remanence of NdFeB.

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Xiao, Fusheng, Wentao Hu, Jianqi Zhao, and Hongmin Zhu. "Technologies of Recycling REEs and Iron from NdFeB Scrap." Metals 13, no. 4 (April 16, 2023): 779. http://dx.doi.org/10.3390/met13040779.

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In recent years, under the background of global low-carbon development, the production of NdFeB magnets has increased dramatically. With the end of magnet life, a large number of discarded products will be produced in the future. At the same time, 6–73% of industrial waste will be produced in the manufacturing process of magnets. The rare earth content (about 30 wt.%) of these magnet scraps is generally higher than that of raw ore, and the recovery of rare earth elements from them helps to stabilize the global rare earth supply chain. In addition, NdFeB scrap contains about 70 wt.% of iron, which is currently unable to be utilized with high added value. If iron can be recycled based on recycling rare earth elements, it is expected to realize the full component recycling of NdFeB waste and reduce the full life cycle environmental load of NdFeB products. This paper summarizes the properties, recycling potential, and existing recycling technologies of NdFeB waste, and it summarizes the principles, advantages, and disadvantages of various recycling methods, such as direct reuse, pyrometallurgy, hydrometallurgy, and electrochemistry. Among them, the electrochemical recovery method was emphatically reviewed as a newly proposed method. On this basis, the future development direction of NdFeB waste recycling has been prospected, and the research idea of avoiding the shortcomings of various recycling methods through the combined process is proposed. It is proposed that low environmental hazards, low energy consumption, and a closed-loop process are the main goals to be achieved in the recycling process.

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Yin, Yu Xia, Rui Jin Hu, Wei Qiang Liu, Ming Yue, and Zhi Chao Zhen. "Comparison and Analysis of Sodium Silicate and Epoxy Bonded NdFeB Magnets." Materials Science Forum 852 (April 2016): 136–41. http://dx.doi.org/10.4028/www.scientific.net/msf.852.136.

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Sodium silicate bonded and epoxy bonded magnetic NdFeB materials are fabricated, respectively. The magnetic properties, temperature coefficient, heat-corrosion and compressive strength of both bonded magnets are investigated. Results reveal that sodium silicate bonded magnet has a similar comprehensive property to epoxy bonded one. Compared to the epoxy bonded magnets, the sodium silicate bonded NdFeB has better temperature coefficient between 20 and 100 °C. The α value of the sodium silicate bonded NdFeB is-0.127 %/°C while the β value is-0.275 %/°C between 20 and 200 °C. DSC thermogram shows that sodium silicate as a bonder in magnet could exist at a higher temperature (above 1000 °C), which is far bigger than the curie point of NdFeB magnet powder. The weight gains of sodium silicate bonded magnet obtained in heat-corrosion resistance test are smaller than those of epoxy bonded one. Compressive strength test shows that sodium silicate bonded magnet has a larger compressive strength (35 MPa) than that of epoxy bonded magnet (27 MPa). Compared to the epoxy, the sodium silicate as bonder in the bonded magnet shows more compact. As a result, the sodium silicate bonded NdFeB bears better magnetic properties, temperature coefficient, heat-corrosion resistant and compressive strength.

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Eriksson, Sandra. "Inherent Difference in Saliency for Generators with Different PM Materials." Journal of Renewable Energy 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/567896.

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The inherent differences between salient and nonsalient electrical machines are evaluated for two permanent magnet generators with different configurations. The neodymium based (NdFeB) permanent magnets (PMs) in a generator are substituted with ferrite magnets and the characteristics of the NdFeB generator and the ferrite generator are compared through FEM simulations. The NdFeB generator is a nonsalient generator, whereas the ferrite machine is a salient-pole generator, with small saliency. The two generators have almost identical properties at rated load operation. However, at overload the behaviour differs between the two generators. The salient-pole, ferrite generator has lower maximum torque than the NdFeB generator and a larger voltage drop at high current. It is concluded that, for applications where overload capability is important, saliency must be considered and the generator design adapted according to the behaviour at overload operation. Furthermore, if the maximum torque is the design criteria, additional PM mass will be required for the salient-pole machine.

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31

Chen, Huan Ming, Ya Hong Gao, Qiong Lv, Dong Yang, and Xin Xin Lin. "Synthesis and Properties of Electroless Ni-P-W/Nano-Al₂O₃ Composite Coatings Deposited on Sintered NdFeB Permanent Magnet." Advanced Materials Research 306-307 (August 2011): 901–6. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.901.

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The Ni-P-W/nano-Al2O3composite coatings were deposited on the surface of sintered NdFeB permanent magnet by electroless plating method. The morphology and the phases of Ni-P-W/nano-Al2O3composite coatings were investigated using scanning electron microscopy and X-ray diffraction respectively. The hardness and the corrosion resistance of the composite coatings were also tested. The results indicated that the composite coatings morphology appears closely nodules morphology, and the microhardness increases with increasing incorporation of Al2O3ratio. Compared with NdFeB magnet and Ni-P-W alloy coatings, the corrosion resistance of the composite coatings was superior to that of the NdFeB magnet and the alloy coating obviously.

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32

Li, Li, Guang Ming Yuan, Zong Wei Niu, and Rong Guo Hou. "Effects of Electrical Discharge Energy on Machining Performance of Sintered NdFeB Magnet." Materials Science Forum 620-622 (April 2009): 711–14. http://dx.doi.org/10.4028/www.scientific.net/msf.620-622.711.

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Sintered NdFeB permanent magnet is widely used in many areas because of its excellent magnet property. In this study, the machining parameters of electrical discharge machining (EDM) are varied to study the effects of electrical discharge energy on material removal rate and surface roughness of NdFeB magnet. Moreover, the micro-cracks on the machined surface induced by EDM are also examined. The experimental results reveal that the MRR increases with the electrical discharge energy. The number of surface cracks on the machined surface increases with the enhancement of discharge energy Thus, using EDM process to machine sintered NdFeB magnet depends on setting the machining parameters to prevent surface crack.

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Xu, Y., L. S. Chumbley, and F. C. Laabs. "Liquid metal extraction of Nd from NdFeB magnet scrap." Journal of Materials Research 15, no. 11 (November 2000): 2296–304. http://dx.doi.org/10.1557/jmr.2000.0330.

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This research involves using molten magnesium (Mg) to remove neodymium (Nd) from NdFeB magnet scrap by diffusion. Mg was melted over pieces of NdFeB scrap and held at temperatures in the range 675–705 °C for 2–8 h. The Mg was allowed to solidify, and the castings were then sectioned and characterized using scanning electron microscopy, x-ray diffraction, and chemical analysis. Nd was found to have diffused out of the solid scrap into the molten Mg. The thickness of the diffusion layer was measured, the diffusion of Nd through the NdFeB scrap into liquid Mg was described, and the diffusion coefficient of Nd in liquid Mg was estimated.

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Mustofa, Salim, Setyo Purwanto, Sumaryo, Bambang Sugeng, Toto Sudiro, Bambang Hermanto, and Nanang Sudrajat. "Early Characterization of NdFeB and NdFeB /Co-Al Composites of Sintering Using SPS." Key Engineering Materials 855 (July 2020): 102–7. http://dx.doi.org/10.4028/www.scientific.net/kem.855.102.

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The purpose of this study is to obtain a permanent magnet end-product from NdFeB and NdFeB / Co-Al composite material from SPS sintering which has high density with small grain size and strong corrosion resistance. NdFeB powder and NdFeB/Co-Al composites (0.2 and 0.5weight%) of several micron-sized particles resulting from the milling process have been successfully sintered with a temperature parameter of 800°C for 10 minutes and a pressure of 50MPa in dies with a diameter of 20 mm in a vacuum chamber. Optical micrographs show that the grains are uniformly and smoothly distributed throughout the surface. This is showing the types of grain distributions which has good mechanical properties. The X-ray analysis result shows the phase analysis confirms the presence of such main PM phases as Nd, Fe and B. From SEM observation, the particles have irregular shapes and a large particle size distribution. The density value of the sample is in the range of 7.1 - 7.3. From the density measurement it is also known that the sintering sample with SPS has a high-density level which is close to 100%, so it can be said that it has formed fully dense.

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Zhang, Hui, Yong Wei Song, and Zhen Lun Song. "Electrodeposited Ni/Al₂O₃ Composite Coating on NdFeB Permanent Magnets." Key Engineering Materials 373-374 (March 2008): 232–35. http://dx.doi.org/10.4028/www.scientific.net/kem.373-374.232.

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NdFeB permanent magnets are highly susceptible to corrosion in various environments. A new composite coating electrodeposited on NdFeB magnets was investigated in this paper. The Ni matrix film was firstly electrodeposited on NdFeB surface from watts nickel electrolyte, and then Ni/Al2O3 composite coating was successively electrodeposited on the Ni film. The microstructures of electrodeposited Ni coating and Ni/Al2O3 composite coating were observed by scanning electron microscopy (SEM). The corrosion behavior of Ni coating and Ni/Al2O3 composite coating in 3.5wt% NaC1 solution was studied by polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the Ni coating and Ni/Al2O3 composite coating could both provide adequate protection to NdFeB substrate. But the free corrosion potential of Ni/Al2O3 composite coating was more positive and the passivation region was more obvious when compared with Ni coating. Meantime, the capacitance loop diameter of Ni/Al2O3 composite coating was significantly larger than that of Ni coating ,which suggested that the anticorrosion resistance of Ni/Al2O3 composite coating was better than electroplated Ni coating.

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36

Li, Li, Siyi Yang, Zongwei Niu, Guangming Zheng, and Zhongwen Sima. "Anticorrosion performance of sintered NdFeB magnets by EDM in different dielectric fluids." Anti-Corrosion Methods and Materials 62, no. 3 (May 5, 2015): 172–75. http://dx.doi.org/10.1108/acmm-01-2015-1487.

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Purpose – This paper aims to present an experimental investigation of improving the surface corrosion resistance of sintered neodymium-iron-boron (NdFeB) magnets by electrical discharge machining (EDM) in different dielectric fluids. Design/methodology/approach – Scanning electron microscope and X-ray diffraction were used to analyze the surface morphology and chemical structure of recast layers formed by EDM using kerosene and distilled water as the dielectric fluids. Polarization scans and electrochemical impedance spectroscopy were applied to investigate the post-machining corrosion resistance. Findings – The test results indicated that the recast layer produced during EDM had amorphous characteristics, and the newly formed amorphous structure could improve the corrosion resistance of the NdFeB material. The corrosion resistance of the recast layer formed in kerosene was better than that formed in distilled water. Originality/value – Surface corrosion modification of sintered NdFeB magnets by means of electrical discharge with an ordinary copper electrode is proposed in this paper. The layer formed by EDM exhibits different behavior to that of the interior of the bulk material and improves the anti-corrosion performance of NdFeB magnets.

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37

Wong, Y. J., H. W. Chang, Y. I. Lee, W. C. Chang, C. H. Chiu, and C. C. Mo. "High-coercivity heavy-rare-earth-free NdFeB sintered magnets developed by doping Ce₈₅Al₁₅ and grain boundary diffusion with Pr₇₀Cu₁₅Al₁₅." AIP Advances 13, no. 2 (February 1, 2023): 025226. http://dx.doi.org/10.1063/9.0000446.

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Traditional NdFeB sintered magnets with coercivity larger than 20 kOe, called super-high (SH) level, usually contains considerable amount of high-cost heavy rare earth (HRE), such as Dy or Tb. In this work, high coercivity of 21.4 kOe, which corresponds to SH level, is achieved for HRE-free NdFeB magnet by doping with Ce85Al15 (CeAl) alloy and grain boundary diffusion (GBD) with Pr70Cu15Al15 (PrCuAl) alloy powders, where Ce/RE ratio is about 15% within the magnet. After GBD treatment with PrCuAl on Ce-containing NdFeB magnets, the formation of Pr-containing shell at 2:14:1 grain surface can increase the local magnetic anisotropy filed and therefore enhance the coercivity. Most of Cu and Al, and parts of Ce and Pr appear at grain boundary and triple junction, which can reduce the magnetization of grain boundary phase, strengthen the decoupling effect between grains and thus contribute to high coercivity. This study provides a cost-effective way to obtain high coercivity for HRE-free NdFeB sintered magnet via doping Ce85Al15 and then GBD with Pr70Cu15Al15.

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38

Aryani, Lia, Bintang Surya Bhakti, Ahmad Riziq Mubarok, Ardita Septiyani, R. Henny Mulyani, Nanang Sudrajat, and Dedi Dedi. "THE EFFECT OF BAKELITE BINDERS ON MAGNETIC PROPERTIES AND HARDNESS VALUES OF MQP-TYPE BONDED NdFeB MAGNETS." Metalurgi 38, no. 2 (October 9, 2023): 49. http://dx.doi.org/10.55981/metalurgi.2023.718.

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Permanent magnets are important in modern society as components in various devices used by many industries and consumers, especially in generators and electric motors. Bonded magnet technology allows combining powdered magnetic materials with polymers as a binder to produce magnetic components that can be applied to certain applications, such as SynRM (synchronous reluctance) motors. Bonded magnets are easy to form without sacrificing their magnetic properties, which are too large, and also reduce costs, making them more effective and efficient. This paper reports the results of a study on the manufacture of bonded magnets NdFeB using bakelite binder on MQP-type NdFeB magnets with a bakelite variation of 0.5 - 2 wt.%. The characterization included testing magnetic properties with Permagraph, morphology with SEM (scanning electron microscope), and hardness values with micro Vickers hardness tester. The results of this study obtained remanence values in the range 5.53 - 6.44 kG and hardness values in the range 341.8 - 507.9 HV for NdFeB bonded magnets. According to SEM observations, the bakelite polymer matrix has successfully bound NdFeB grains, and no porosity is visible.

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de Campos, Marcos Flavio, Daniel Rodrigues, and Jose Adilson de Castro. "Replacement of NdFeB by Ferrite Magnets." Materials Science Forum 912 (January 2018): 106–11. http://dx.doi.org/10.4028/www.scientific.net/msf.912.106.

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The replacement of NdFeB magnets by ferrite magnets is discussed. For motors, remanence is relevant, implying in a volume three times that of NdFeB, when the relevant index of merit is remanence. However, if the relevant issue is the BHmax (maximum energy product), the volume for replacement should be ten times larger. The high resistivity of ferrites is a big advantage for motors. The temperature of operation is also relevant, because NdFeB magnets loss coercivity even with small increase of temperature. Different applications are discussed, as for instance, motors for electric cars and wind turbines. The choice of the proper volume depends on the evaluation of demagnetizing field in the condition of operation.

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Li, Li, F. F. Wang, and Zong Wei Niu. "Ultrasonic Machining Aided Tool Rotation of Sintered NdFeB Magnet." Applied Mechanics and Materials 52-54 (March 2011): 210–13. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.210.

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A new kind of ultrasonic machining is proposed for sintered NdFeB permanent magnet. Experiments were carried out on self-made equipment. Test results showed that the MRR would increase with the amplitude of tool, static load and the size of abrasive grain at certain range. This kind of ultrasonic machining is a suitable method for machining NdFeB material.

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41

Liu, A. Z., I. Z. Rahman, M. A. Rahman, M. O'Riordan, and E. Petty. "NdFeB in Automotive Applications." Key Engineering Materials 72-74 (January 1992): 295–302. http://dx.doi.org/10.4028/www.scientific.net/kem.72-74.295.

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42

Ma, B., V. Chandhok, and E. Dulis. "Radially oriented NdFeB magnets." IEEE Transactions on Magnetics 23, no. 5 (September 1987): 2518–20. http://dx.doi.org/10.1109/tmag.1987.1065350.

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43

ALECU, GEORGETA, and WILHELM KAPPEL. ""Elements of circular economy in the manufacture of NdFeB permanent magnets IN ICPE-CA "." Journal of Engineering Sciences and Innovation 6, no. 2 (May 17, 2021): 175–88. http://dx.doi.org/10.56958/jesi.2021.6.2.7.

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"In the life cycle of the product, the link between the initial phase and the final stage in its realization is the recycling through the rehabilitation of materials in the production process. This gives circularity to the economy, thus minimizing consumption of natural resources, optimizing manufacturing costs, creating new jobs, developing business. The paper describes in a conclusive example the defining elements of the circular economy. We present this example for the simplicity of our demonstration. This mode allows a direct and edifying treatment of the defining elements of the circular economy. We have chosen as a product the permanent magnets based on rare earths of the NdFeB type. The choice is targeted because NdFeB permanent magnets are expensive products, so the benefits being obvious. We demonstrate the manufacturing of NdFeB permanent magnets with defined magnetic properties from raw materials, their use in products (for ex. in synchronous electric motors) and at the end of the life cycle of motors, the recovery of permanent magnets with the possibility of obtaining the powders used initially in the technological process to manufacture new NdFeB permanent magnets with similar magnetic properties and the possibility of their use in electrotechnical products. Even if, following a piece to piece sorting of the permanent magnets after magnetic parameters of the resulting products would remain scrap, they could be recycled in the same way so that the amount of waste would ultimately be minimal. Finally, we present a recycling technology of NdFeB permanent magnets based on one of our patents filed in 1998. "

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Kaya, Elif Emil, Ozan Kaya, Srecko Stopic, Sebahattin Gürmen, and Bernd Friedrich. "NdFeB Magnets Recycling Process: An Alternative Method to Produce Mixed Rare Earth Oxide from Scrap NdFeB Magnets." Metals 11, no. 5 (April 27, 2021): 716. http://dx.doi.org/10.3390/met11050716.

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Neodymium iron boron magnets (NdFeB) play a critical role in various technological applications due to their outstanding magnetic properties, such as high maximum energy product, high remanence and high coercivity. Production of NdFeB is expected to rise significantly in the coming years, for this reason, demand for the rare earth elements (REE) will not only remain high but it also will increase even more. The recovery of rare earth elements has become essential to satisfy this demand in recent years. In the present study rare earth elements recovery from NdFeB magnets as new promising process flowsheet is proposed as follows; (1) acid baking process is performed to decompose the NdFeB magnet to increase in the extraction efficiency for Nd, Pr, and Dy. (2) Iron was removed from the leach liquor during hydrolysis. (3) The production of REE-oxide from leach liquor using ultrasonic spray pyrolysis method. Recovery of mixed REE-oxide from NdFeB magnets via ultrasonic spray pyrolysis method between 700 °C and 1000 °C is a new innovative step in comparison to traditional combination of precipitation with sodium carbonate and thermal decomposition of rare earth carbonate at 850 °C. The synthesized mixed REE- oxide powders were characterized by X-ray diffraction analysis (XRD). Morphological properties and phase content of mixed REE- oxide were revealed by scanning electron microscopy (SEM) and Energy-dispersive X-ray (EDX) analysis. To obtain the size and particle size distribution of REE-oxide, a search algorithm based on an image-processing technique was executed in MATLAB. The obtained particles are spherical with sizes between 362 and 540 nm. The experimental values of the particle sizes of REE- oxide were compared with theoretically predicted ones.

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45

Piotrowicz, A., S. Pietrzyk, P. Noga, and Ł. Mycka. "The use of thermal hydrogen decrepitation to recycle Nd-Fe-B magnets from electronic waste." Journal of Mining and Metallurgy, Section B: Metallurgy, no. 00 (2020): 32. http://dx.doi.org/10.2298/jmmb200207032p.

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Rare earth magnets based upon neodymium-iron-boron (NdFeB) are employed in many high tech applications, including hard disk drives (HDDs). The key elements in manufacturing NdFeB magnets are rare earth elements (REEs) such as neodymium. This element has been subject to significant supply shortfalls in the recent past. Recycling of NdFeB magnets contained within waste of electrical and electronic equipment (WEEE) could provide a secure and alternative supply of these materials. Various recycling approaches for the recovery of sintered NdFeB magnets have been widely explored. Hydrogen decrepitation (HD) can be used as a direct reuse approach and effective method of recycling process to turn solid sintered magnets into a demagnetised powder for further processing. In this work, sintered Nd-Fe-B magnets were processed without prior removal of the metallic protective layer using the thermal HD process as an alternative recycling method. The gas sorption analyzer have been used to determine the quantity of the hydrogen absorbed by a samples of magnets, under controlled pressure (1, 2, 3 and 4 bar) and temperature (room, 100, 300 and 400?C) conditions, using Sieverts? volumetric method. The composition and morphology of the starting and the extracted/disintegrated materials were examined by ICP, XRD and SEM-EDS analysis.

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Reimer, Maximilian, Heike Schenk-Mathes, Matthias Hoffmann, and Tobias Elwert. "Recycling Decisions in 2020, 2030, and 2040—When Can Substantial NdFeB Extraction be Expected in the EU?" Metals 8, no. 11 (October 24, 2018): 867. http://dx.doi.org/10.3390/met8110867.

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In recent years, China’s dominant role in the rare earth market and the associated impacts have strengthened the interest in the recovery of rare earth elements (REE) from secondary resources. Therefore, numerous research activities have been initiated aiming at the recovery of REEs from different types of waste streams, which includes, inter alia, neodymium-iron-boron (NdFeB) magnets. Although several research projects have successfully been completed, most experts do not expect an industrial implementation in Europe within the next years. This article analyses the reasons for this situation, addressing the availability of sufficient amounts of NdFeB wastes, the technology readiness level of the developed processes in Europe, as well as the economic aspects. Based on these analyses, an estimation of a realistic timeframe for the industrial implementation of NdFeB recycling in Europe is deduced and critically discussed.

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47

Urse, M., M. Grigoras, N. Lupu, and H. Chiriac. "Structural and magnetic properties of NdFeB and NdFeB/Fe films with Mo addition." Journal of Physics: Conference Series 303 (July 6, 2011): 012009. http://dx.doi.org/10.1088/1742-6596/303/1/012009.

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48

Salas, F. H., C. Dehesa, G. T. Pérez, and J. M. Alameda. "Magnetic and magneto-optical properties of NdFeB/Mo and NdFeB/FeB amorphous bilayers." Journal of Magnetism and Magnetic Materials 121, no. 1-3 (March 1993): 548–51. http://dx.doi.org/10.1016/0304-8853(93)91267-b.

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Qin, Wan Zhong. "The Mold for Bonded NdFeB Magnet Compression Molding." Applied Mechanics and Materials 633-634 (September 2014): 747–50. http://dx.doi.org/10.4028/www.scientific.net/amm.633-634.747.

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Compression molding is the most important method to gain high quality bonded NdFeB magnets. The production process is preparation of composite powder, compression molding, coating and magnetizing. Based on test and lot production practice, the important effects of compression molding actions, mould structure and mould material on magnet quality are analyzed. The mold structures for ring-magnet and arc-magnet are fixed. The key techniques that controlling the quality of bonded NdFeB magnets are summarized.

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Sampaio da Silva, Fernanda A., and Marcos Flavio de Campos. "A Simple Algorithm for the Calculation of Hysteresis for Isotropic NdFeB Magnets." Materials Science Forum 727-728 (August 2012): 119–23. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.119.

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The calculation of hysteresis curves with the Stoner-Wohlfarth model is somewhat laborious. For the Nd2Fe14B phase, the second order magnetocrystalline anisotropy (K2) constant is relevant, and this case only has been discussed in some studies. In this article, a simple algorithm for the calculation of the Stoner-Wohlfarth model for isotropic NdFeB magnets is described. This algorithm makes easier the modeling of the hysteresis curves of bonded melt-spun NdFeB magnets.

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Journal articles on the topic 'NdFeB'

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