scholarly journals An Overview of MnAl Permanent Magnets with a Study on Their Potential in Electrical Machines

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5549
Author(s):  
Sofia Kontos ◽  
Anar Ibrayeva ◽  
Jennifer Leijon ◽  
Gustav Mörée ◽  
Anna E. Frost ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Saturation Magnetization ◽  
Permanent Magnets ◽  
Electrical Machines ◽  
Ndfeb Magnet ◽  
Hard Magnetic Materials ◽  
Carbon Doped ◽  
Energy Products ◽  
Comsol Simulation ◽  
Future Work

In this paper, hard magnetic materials for future use in electrical machines are discussed. Commercialized permanent magnets used today are presented and new magnets are reviewed shortly. Specifically, the magnetic MnAl compound is investigated as a potential material for future generator designs. Experimental results of synthesized MnAl, carbon-doped MnAl and calculated values for MnAl are compared regarding their energy products. The results show that the experimental energy products are far from the theoretically calculated values with ideal conditions due to microstructure-related reasons. The performance of MnAl in a future permanent magnet (PM) generator is investigated with COMSOL, assuming ideal conditions. Simplifications, such as using an ideal hysteresis loop based on measured and calculated saturation magnetization values were done for the COMSOL simulation. The results are compared to those for a ferrite magnet and an NdFeB magnet. For an ideal MnAl hysteresis loop, it would be possible to replace ferrite with MnAl, with a reduced weight compared to ferrite. In conclusion, future work for simulations with assumptions and results closer to reality is suggested.

scholarly journals Developing a reference material set for the magnetic properties of NdFeB alloy-based hard magnetic materials

2019 ◽  
Vol 15 (1) ◽  
pp. 21-27
Author(s):  
E. A. Volegova ◽  
T. I. Maslova ◽  
V. O. Vas’kovskiy ◽  
A. S. Volegov
Keyword(s):  
Magnetic Properties ◽  
Magnetic Materials ◽  
Permanent Magnets ◽  
Magnetic Loss ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Magnetic Hysteresis Loop ◽  
Magnetic Characteristics ◽  
Hard Magnetic Materials ◽  
Certified Values

Introduction The introduction indicates the need for the use of permanent magnets in various technology fields. The necessity of measuring the limit magnetic hysteresis loop for the correct calculation of magnetic system parameters is considered. The main sources of error when measuring boundary hysteresis loops are given. The practical impossibility of verifying blocks of magnetic measuring systems element-by-element is noted. This paper is devoted to the development of reference materials (RMs) for the magnetic properties of hard magnetic materials based on Nd2Fe14B, a highly anisotropic intermetallic compound.Materials and measuring methods Nd-Fe-B permanent magnets were selected as the material for developing the RMs. RM certified values were established using a CYCLE‑3 apparatus included in the GET 198‑2017 State Primary Measurement Standard for units of magnetic loss power, magnetic induction of constant magnetic field in a range from 0.1 to 2.5 T and magnetic flux in a range from 1·10–5 to 3·10–2 Wb.Results and its discussion Based on the experimentally obtained boundary hysteresis loops, the magnetic characteristics were evaluated, the interval of permitted certified values was set, the measurement result uncertainty of certified values was estimated, the RM validity period was established and the first RM batch was released.Conclusion On the basis of conducted studies, the RM type for magnetic properties of NdFeB alloy-based hard magnetic materials was approved (MS NdFeB set). The developed RM set was registered under the numbers GSO 11059–2018 / GSO 11062–2018 in the State RM Register of the Russian Federation.

Investigation of magnet segmentation techniques for eddy current losses reduction in permanent magnets electrical machines

2015 ◽  
Vol 34 (1) ◽  
pp. 46-60 ◽  
Author(s):  
Belli Zoubida ◽  
Mohamed Rachid Mekideche
Keyword(s):  
Genetic Algorithm ◽  
Finite Elements ◽  
Eddy Current ◽  
Permanent Magnets ◽  
Skin Effect ◽  
Electrical Machines ◽  
Design Parameters ◽  
Finite Elements Analysis ◽  
Eddy Current Losses ◽  
Content Type

Purpose – Reducing eddy current losses in magnets of electrical machines can be obtained by means of several techniques. The magnet segmentation is the most popular one. It imposes the least restrictions on machine performances. This paper investigates the effectiveness of the magnet circumferential segmentation technique to reduce these undesirable losses. The full and partial magnet segmentation are both studied for a frequency range from few Hz to a dozen of kHz. To increase the efficiency of these techniques to reduce losses for any working frequency, an optimization strategy based on coupling of finite elements analysis and genetic algorithm is applied. The purpose of this paper is to define the parameters of the total and partial segmentation that can ensure the best reduction of eddy current losses. Design/methodology/approach – First, a model to analyze eddy current losses is presented. Second, the effectiveness of full and partial magnet circumferential segmentation to reduce eddy loss is studied for a range of frequencies from few Hz to a dozen of kHz. To achieve these purposes a 2-D finite element model is developed under MATLAB environment. In a third step of the work, an optimization process is applied to adjust the segmentation design parameters for best reduction of eddy current losses in case of surface mounted permanent magnets synchronous machine. Findings – In case of the skin effect operating, both full and partial magnet segmentations can lead to eddy current losses increases. Such deviations of magnet segmentation techniques can be avoided by an appropriate choice of their design parameters. Originality/value – Few works are dedicated to investigate partial magnet segmentation for eddy current losses reduction. This paper studied the effectiveness and behaviour of partial segmentation for different frequency ranges. To avoid eventual anomalies related to the skin effect an optimization process based on the association of the finite elements analysis to genetic algorithm method is adopted.

scholarly journals Magnetic and Structural Properties of Barium Hexaferrite Nanoparticles Doped with Titanium

Symmetry ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 732 ◽  
Author(s):  
Abdul Raouf Al Dairy ◽  
Lina A. Al-Hmoud ◽  
Heba A. Khatatbeh
Keyword(s):  
Saturation Magnetization ◽  
Permanent Magnets ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Barium Hexaferrite ◽  
Titanium Concentration ◽  
Recording Equipment ◽  
Auto Combustion ◽  
Xrd Patterns ◽  
Combustion Technique

Samples of Barium Hexaferrite doped with Titanium BaFe12−xTixO19 with (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were synthesized by the sol–gel auto-combustion technique. The powdered samples were divided into two parts, one sintered at 850 °C and another sintered 1000 °C for 1 h and samples were characterized by different experimental techniques. The XRD patterns confirmed the presence of M-type hexaferrite phase. The sizes of the crystallites were calculated by the Scherer equation, and the sizes were in the range of 27–42 nm. Using the hysteresis loops, the saturation magnetization Ms, remanence (Mr), the relative ratio (Mr/Ms), and the coercivity (Hc) were calculated. The study showed that the saturation magnetization (Ms) and remanence (Mr) decreased with increasing titanium concentration and were in the range from 44.65–17.17 emu/g and 23.1–7.7 emu/g, respectively. The coercivity (Hc) ranged between 0.583 and 4.51 (kOe). The magnetic properties of these Barium Hexaferrite doped with Titanium indicated that they could be used in the recording equipment and permanent magnets.

scholarly journals Magnetic Properties of SmCo5 + 10 wt% Fe Exchange-Coupled Nanocomposites Produced from Recycled SmCo5

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1308 ◽  
Author(s):  
Arnab Chakraborty ◽  
Răzvan Hirian ◽  
Gregor Kapun ◽  
Viorel Pop
Keyword(s):  
Heat Treatment ◽  
Exchange Coupling ◽  
Permanent Magnets ◽  
High Energy ◽  
Raw Material ◽  
Energy Ball ◽  
Hydrogen Decrepitation ◽  
Energy Products ◽  
First Time ◽  
Recycled Material

Nanostructured alloy powders of SmCo5 + 10 wt% Fe obtained using recycled material were studied for the first time. The SmCo5 precursor was obtained from commercial magnets recycled by hydrogen decrepitation. The results were compared with identically processed samples obtained using virgin SmCo5 raw material. The samples were synthesized by dry high-energy ball-milling and subsequent heat treatment. Robust soft/hard exchange coupling was observed—with large coercivity, which is essential for commercial permanent magnets. The obtained energy products for the recycled material fall between 80% and 95% of those obtained when using virgin SmCo5, depending on milling and annealing times. These results further offer viability of recycling and sustainability in production. These powders and processes are therefore candidates for the next generation of specialized and nanostructured exchange-coupled bulk industrial magnets.

Misch-Metal and/or Aluminum Substitutions in ND-FE-B Permanent Magnets

1987 ◽  
Vol 96 ◽  
Author(s):  
B. M. Ma ◽  
C. J. Willzian
Keyword(s):  
Rare Earth ◽  
Permanent Magnets ◽  
Alloy System ◽  
Magnetic Characteristics ◽  
Al Doping ◽  
Sintered Magnet ◽  
Al Content ◽  
Misch Metal ◽  
Heavy Rare Earth Elements ◽  
Energy Products

ABSTRACTThe effects of misch-metal–and/or Al substitutions in the Nd-Fe-B alloy system have been investigated. Selected compositions were processed into magnets using the conventional powder metallurgy technique. As expected, misch-metal substitutions act to degrade the intrinsic magnetic characteristics and thus degrade the properties of the sintered magnet. It was observed that at a level of 25% of the total rare earth being comprised of misch-metal, energy products of the order of 25 MGOe were still able to be achieved. Processing of such material is difficult because higher sintering temperatures are required to fully densify the magnet, and the grain growth that occurs at these temperatures dramatically reduces the coercivity. The effects of misch-metal substitutions are quantified in this discussion.Al was found to be beneficial for improving the coercivity in both the Nd-Fe-B and misch-metal-Fe-B alloy systems. Unfortunately Al substitutions reduce both the remanence and the Curie temperature. If the Al content is kept to 1 wt.% or less, magnets exhibiting reasonable properties can be made. Al doping as opposed to doping with expensive heavy rare earth elements such as Th or Dy is a less costly method of improving Hei, in the Nd-Fe-B magnets.

Demonstration of high-performance pole pieces made of monocrystalline dysprosium for short-period undulators

2019 ◽  
Vol 26 (4) ◽  
pp. 1220-1225
Author(s):  
Takashi Tanaka ◽  
Akihiro Kagamihata
Keyword(s):  
Magnetic Flux ◽  
Curie Temperature ◽  
Saturation Magnetization ◽  
High Performance ◽  
Permanent Magnets ◽  
Magnetic Performance ◽  
Short Period ◽  
Conventional Material ◽  
Selection Of

Reported here are the results of experiments carried out to demonstrate the magnetic performance of dysprosium (Dy) to enhance the capability of undulators. Tiny pieces of monocrystalline Dy surrounded by permanent magnets (PMs) work as pole pieces (PPs) to concentrate the magnetic flux, when cooled down below the Curie temperature of 85 K. A PP made of Dy is much more attractive than one made of a conventional material, because its saturation magnetization is much higher. Furthermore, it also allows for a more flexible selection of PM material, potentially leading to further enhancement of the performance of short-period undulators. Besides these advantages, practical issues related to using Dy PPs and countermeasures against them are discussed.

Handling and Fixation of Permanent Magnets

2013 ◽  
Vol 769 ◽  
pp. 3-10 ◽  
Author(s):  
Jan Tremel ◽  
Benjamin Hofmann ◽  
Florian Risch
Keyword(s):  
Rare Earth ◽  
Permanent Magnet ◽  
Electric Vehicles ◽  
Permanent Magnets ◽  
Electrical Machines ◽  
Research Projects ◽  
Fixation Methods ◽  
High Efficient ◽  
The Family

Due to rapid developments within the family of rare-earth materials innovative electrical machines can nowadays be used as high efficient generators in various power, as well as rugged constructed machines for automobile battery based propulsion in hybrid and full electric vehicles. The production of different motor concepts spread into different design variants and creates complex variations especially regarding the rotor. Deriving from various research projects, the handling of the permanent magnet components is investigated, including the development of new assembly and fixation methods.

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