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Title: Strategic coating of NdFeB magnets with Dy to improve the coercivity of permanent magnets

Here, we present a method, supported by theoretical analysis, for optimizing the usage of the critical rare earth element dysprosium in Nd 2Fe 14B (NdFeB)-based permanent magnets. In this method, we use Dy selectively in locations such as magnet edges and faces, where demagnetization factors are most significant, rather than uniformly throughout the bulk sample. A 200 nm thick Dy film was sputtered onto commercial N-38, NdFeB magnets with a thickness of 3 mm and post-annealed at temperatures from 600 - 700 C. Magnets displayed enhanced coercivities after post-annealing. Furthermore, our experimental results indicate as large as a 5 percent increase in the energy product of NdFeB magnets, achieved for a total Dy weight percentage of 0.06 percent, much less than that used in commercial grade Dy-NdFeB magnets. Finally, by assuming all Dy diffused into NdFeB magnets, the improvement in energy product corresponds to a saving of over 1% Dy (critical element). Magnets manufactured using this technique will therefore be higher performing and significantly less expensive than those made presently.
 [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Ames Lab., Ames, IA (United States)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2234-0912
Grant/Contract Number:
AC05-00OR22725; AC52-07NA27344
Accepted Manuscript
Journal Name:
Advances in Materials Research
Additional Journal Information:
Journal Volume: 4; Journal Issue: 4; Journal ID: ISSN 2234-0912
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Critical Materials Institute (CMI); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Advanced Manufacturing Office (EE-5A)
Country of Publication:
United States
36 MATERIALS SCIENCE; NdFeB magnets; sputter deposition; selective Dy diffusion; magnetic properties; theoretical analysis
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1409963