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This content will become publicly available on December 25, 2016

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 Nd2Fe14B (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.
Authors:
 [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:
OSTI Identifier:
1286953
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Advances in Materials Research
Additional Journal Information:
Journal Volume: 4; Journal Issue: 4; Journal ID: ISSN 2234-0912
Publisher:
Techno-Press
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Critical Materials Institute (CMI)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Advanced Manufacturing Office (EE-5A)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE NdFeB magnets; sputter deposition; selective Dy diffusion; magnetic properties; theoretical analysis