Sm2Fe17N3 as a cost-effective high-performance magnet

Powder X-ray diffraction patterns of as-washed and sintered material. 
Powder X-ray diffraction patterns of as-washed and sintered material. 

CMI researchers at Ames National Laboratory conducted the research for this highlight

Innovation
Conversion of Sm2O3 into Sm2Fe17 phase via reduction-diffusion approach produces nearly oxygen-free, sinterable Sm2Fe17N3 powders.

Achievement
Synthesis of Sm2Fe17 powders directly from Sm2O3 leads to a magnet that after nitrogenation and sintering at 420°C reaches a relative density of 86% and shows substantially improved hard-magnetic properties, with energy product, BHmax=16.6 MGOe.

Significance and Impact

  • Criticality and cost: the material is mostly Fe (~74% wt.%) and it contains non-critical rare earth, Sm, as well as other earth-abundant constituents.
  • When fully developed, thermally-stable Sm2Fe17N3–based materials are expected to become competitive with Nd2Fe14B-based magnets.

Hub Goal Addressed 
Reducing critical rare-earth content in strong permanent magnets. 

Hysteresis loops of corresponding samples.
Hysteresis loops of corresponding samples.