Initial Irreversible Losses and Enhanced High-Temperature Performance of Rare-Earth Permanent Magnets

Wei Xia, Yangkun He, Houbing Huang, Hui Wang, Xiaoming Shi, Tianli Zhang, Jinghua Liu, Plamen Stamenov, Long-qing Chen, John Michael David Coey, Chengbao Jiang

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

There is an increasing demand for permanent magnets with high-temperature stability. Normally, the magnets are heat treated above the operating temperature range to saturate the irreversible losses, thereby producing magnets that are stable, but with significantly degraded performance. In addition, uncertainty about the losses in differently shaped magnets causes difficulties for efficient magnetic circuit design. The variation of the initial irreversible losses with magnet shape, hysteresis loop, and operating temperature is presented here. Losses are not associated with thermal demagnetization of the whole magnet, but the damage is concentrated in an outer surface “skin” at the pole surfaces, where the demagnetizing field is nonuniform. The initial irreversible remanence loss at room temperature (Formula presented.) can be predicted as the product of the slope of the high-temperature magnetization curve k(T) and the effective demagnetizing factor N. Heat treatment with the vulnerable surfaces in contact with soft iron slabs moves the skin out of the permanent magnet and reduces the irreversible remanence loss by 30% or more, potentially improving the performance of permanent-magnet motors, generators, bearings, and thrusters. The results deepen the understanding of the magnetism of irreversible losses and will guide the applications of permanent magnets at higher temperatures.

Original languageEnglish (US)
Article number1900690
JournalAdvanced Functional Materials
Volume29
Issue number24
DOIs
StatePublished - Jun 13 2019

Fingerprint

permanent magnets
Rare earths
Permanent magnets
rare earth elements
Magnets
magnets
Remanence
Temperature
remanence
operating temperature
Skin
Bearings (structural)
Demagnetization
magnetic circuits
Magnetic circuits
Magnetism
demagnetization
Hysteresis loops
Poles
Magnetization

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrochemistry

Cite this

Xia, Wei ; He, Yangkun ; Huang, Houbing ; Wang, Hui ; Shi, Xiaoming ; Zhang, Tianli ; Liu, Jinghua ; Stamenov, Plamen ; Chen, Long-qing ; Coey, John Michael David ; Jiang, Chengbao. / Initial Irreversible Losses and Enhanced High-Temperature Performance of Rare-Earth Permanent Magnets. In: Advanced Functional Materials. 2019 ; Vol. 29, No. 24.
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Xia, W, He, Y, Huang, H, Wang, H, Shi, X, Zhang, T, Liu, J, Stamenov, P, Chen, L, Coey, JMD & Jiang, C 2019, 'Initial Irreversible Losses and Enhanced High-Temperature Performance of Rare-Earth Permanent Magnets', Advanced Functional Materials, vol. 29, no. 24, 1900690. https://doi.org/10.1002/adfm.201900690

Initial Irreversible Losses and Enhanced High-Temperature Performance of Rare-Earth Permanent Magnets. / Xia, Wei; He, Yangkun; Huang, Houbing; Wang, Hui; Shi, Xiaoming; Zhang, Tianli; Liu, Jinghua; Stamenov, Plamen; Chen, Long-qing; Coey, John Michael David; Jiang, Chengbao.

In: Advanced Functional Materials, Vol. 29, No. 24, 1900690, 13.06.2019.

Research output: Contribution to journalArticle

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AU - Zhang, Tianli

AU - Liu, Jinghua

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AU - Coey, John Michael David

AU - Jiang, Chengbao

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