Recent advances in hard ­ferrite magnets

Bollero, A.; Palmero, Ester M.

doi:10.1016/b978-0-323-88658-1.00013-3

Cited by 10 publications

(8 citation statements)

References 115 publications

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“…Nevertheless, ferrite and Mn−Al−C magnets could represent the best option for less energy-intensive applications such as power window/seats in vehicles, switches, fans, blowers in appliances, some power tools, and loudspeakers and buzzers in electro-acoustic devices, 13 but also in the motors of some e-vehicles (e-scooter, e-bike, and emotorbike) by taking advantage of the possibility of an easy implementation of redesigns. 9 Another aspect to take into account is that ferrite magnets show much lower electrical conductivity than Nd−Fe−B magnets; that is translated into lower losses due to eddy currents, thus reducing demagnetization phenomena. 79 These aspects, combined with the obtained sustainability results, prove that it is worth investing in scientific and technological research to enhance the properties and applications of RE-free magnets properties and applications.…”

Section: ■ Discussionmentioning

confidence: 99%

“…7,8 Nowadays, the family of hexagonal ferrites, already implemented in multiple applications, is the candidate for a partial rare-earth magnets substitution thanks to the improved performance in combination with the possibility of optimizing the design of products to take full advantage from the enhanced properties. 9 More recently, also the ferromagnetic Mn−Al-based compounds are gaining attention for their potential to become new hard magnetic materials commercially available. 10 Hard M-type hexaferrite magnets, also known as ceramic magnets, are characterized by low cost, very good corrosion resistance, and high temperature stability (up to 250 °C).…”

Section: ■ Introductionmentioning

confidence: 99%

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Life Cycle Assessment of Rare Earth Elements-Free Permanent Magnet Alternatives: Sintered Ferrite and Mn–Al–C

Amato,

Becci,

Bollero

et al. 2023

ACS Sustainable Chem. Eng.

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Permanent magnets are fundamental constituents in key sectors such as energy and transport, but also robotics, automatization, medicine, etc. High-performance magnets are based on rare earth elements (RE), included in the European list of critical raw materials list. The volatility of their market increased the research over the past decade to develop RE-free magnets to fill the large performance/cost gap existing between ferrites and RE-based magnets. The improvement of hard ferrites and Mn–Al–C permanent magnets plays into this important technological role in the near future. The possible substitution advantage was widely discussed in the literature considering both magnetic properties and economic aspects. To evaluate further sustainability aspects, the present paper gives a life cycle assessment quantifying the environmental gain resulting from the production of RE-free magnets based on traditional hexaferrite and Mn–Al–C. The analysis quantified an advantage of both magnets that overcomes the 95% in all the considered impact categories (such as climate change, ozone depletion, human toxicity) compared to RE-based technologies. The benefit also includes the health and safety of working time aspects, proving possible reduction of worker risks by 3–12 times. The results represent the fundamentals for the development of green magnets that are able to significantly contribute to an effective sustainable transition.

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Section: ■ Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Life Cycle Assessment of Rare Earth Elements-Free Permanent Magnet Alternatives: Sintered Ferrite and Mn–Al–C

Amato,

Becci,

Bollero

et al. 2023

ACS Sustainable Chem. Eng.

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“…In addition, four over pi indicates the fundamental component of square wave. Consequently, the back EMF is formulated as equation (11), where the ω e is electrical angular rotational speed.…”

Section: A Back Electromotive Forcementioning

confidence: 99%

“…Therefore, the ferrite magnet is robust at higher temperatures. Moreover, price competitiveness is good and there is no supply vulnerability of materials for manufacturing [11].…”

Section: Introductionmentioning

confidence: 99%

Speed Response Improvement Design of Electric Motor for Vehicle Electrification Based on Electro-Mechanical Analytic Model

Dong-min

Lim

2023

IEEE Access

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According to vehicle electrification trends, the application of electric motors more often occurs. Therefore, in the aspect of the supply instability preparation for rare-earth materials, research on the rare-earth-free motor is getting more attention. Moreover, the electric motor for the vehicles should have not only high power density but also fast response. Especially, electric motors for advanced driver assistant systems (ADAS) or autonomous driving vehicles should have a fast response speed to secure the driver's safety. This paper introduces the electro-mechanical response improvement design of concentrated flux synchronous motors for vehicle electrification. Improvement design is carried out targeting motors for electric power steering (EPS) system. The development of the electro-mechanical analytic (MEA) model of the electric motor is firstly explained. Then, based on the developed MEA model, electro-mechanical response modeling is performed. Finally, the speed response improvement design is conducted using the developed MEA model. In addition, the results are validated not only in finite element analysis but also experimentally.INDEX TERMS Concentrated flux synchronous motor (CFSM), electric power steering (EPS), rare-earth free motor, rise time, settling time, speed response.

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“…Hexaferrites, particularly SrFe 12 O 19 , cover 80% of the volume of magnets sold every year, reaching an annual production of 800 kilotons. The main advantages offered by ferrites include availability, price, and environmental friendliness during both mining and production. , The intrinsic characteristics of hexaferrites make them a suitable green alternative to rare-earth-based magnets in a variety of applications, such as small electric motors, microwave devices, recording media, telecommunication, electric industry, and also in micro- and nanosystems, such as biomarkers, biodiagnostics, and biosensors. ,− Strontium hexaferrite is a ferrimagnetic material, with a moderate saturation magnetization of 75 A m 2 /kg compared with magnetite, Fe 3 O 4 , 95 A m 2 /kg. , However, the uniaxial magnetocrystalline anisotropy is tightly bound to its hexagonal c -axis and allows strontium hexaferrite to be an excellent candidate for permanent magnet applications …”

Section: Introductionmentioning

confidence: 99%

High-Performance Hexaferrite Ceramic Magnets Made from Nanoplatelets of Ferrihydrite by High-Temperature Calcination for Permanent Magnet Applications

Vijayan

Laursen

Stingaciu

et al. 2023

ACS Appl. Nano Mater.

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Highly aligned ceramic hexaferrite magnets with high-energy products (BH) max and a density exceeding 90% of theoretical density have been fabricated. The precursors were an antiferromagnetic powder, a six-line ferrihydrite mixed with SrCO 3 , and a grain growth inhibitor SiO 2 . Conventional cold compaction of the precursor powders was employed prior to calcination at temperatures of 1050, 1150, and 1250 °C. The influence of calcination temperature and magnetic properties has been systematically studied in the produced ceramic magnets. Conventional cold compaction is a favorable route for industrial production when compared with other compaction techniques like spark plasma sintering, hot compaction, or electroforging. A high (BH) max of 25.2 kJ/m 3 was obtained for the best magnet along with an appreciable coercivity, H c , of 187 kA m −1 , a high squareness ratio, M r /M s , of 0.84, and a saturation magnetization, M s , of 73 A m 2 /kg. Texture and crystallite size analysis were extracted from 2D synchrotron transmission powder diffraction measurements. We have demonstrated that high-performance bulk magnets for permanent magnet applications can be produced from nonmagnetic interacting crystallites mixed with a grain growth inhibitor without applying a magnetic field for alignment.

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Recent advances in hard ferrite magnets

Cited by 10 publications

References 115 publications

Life Cycle Assessment of Rare Earth Elements-Free Permanent Magnet Alternatives: Sintered Ferrite and Mn–Al–C

Life Cycle Assessment of Rare Earth Elements-Free Permanent Magnet Alternatives: Sintered Ferrite and Mn–Al–C

Speed Response Improvement Design of Electric Motor for Vehicle Electrification Based on Electro-Mechanical Analytic Model

High-Performance Hexaferrite Ceramic Magnets Made from Nanoplatelets of Ferrihydrite by High-Temperature Calcination for Permanent Magnet Applications

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Recent advances in hard ­ferrite magnets

Cited by 10 publications

References 115 publications

Life Cycle Assessment of Rare Earth Elements-Free Permanent Magnet Alternatives: Sintered Ferrite and Mn–Al–C

Life Cycle Assessment of Rare Earth Elements-Free Permanent Magnet Alternatives: Sintered Ferrite and Mn–Al–C

Speed Response Improvement Design of Electric Motor for Vehicle Electrification Based on Electro-Mechanical Analytic Model

High-Performance Hexaferrite Ceramic Magnets Made from Nanoplatelets of Ferrihydrite by High-Temperature Calcination for Permanent Magnet Applications

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Recent advances in hard ferrite magnets