A simple method for demagnetizing large NdFeB permanent magnets

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Prior to processing magnetic NdFeB material for recycling it must be demagnetised. Here we demonstrate a simple low-cost method. Large blocks of NdFeB permanent magnets of dimension 10 cm × 7 cm × 2 cm and with the easy axis along the shortest dimension, are shown to demagnetise when heated on a planar induction heating device. The initial magnetisation of the magnets is reduced by a factor of 10 within a period of 30 minutes, in which the surface temperature of the magnet reaches 225 °C. This method simplifies the demagnetisation process of the permanent magnets in wind turbine generators as part of the rapidly increasing demand for improved recycling capabilities of permanent magnets.
Original languageEnglish
JournalIEEE Transactions on Magnetics
Issue number8
Number of pages6
Publication statusPublished - 2020


  • Permanent magnet
  • Recycling
  • Induction heating
  • Permanent magnet generators
  • Wind turbines


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