Tailored synthesis in nanoparticle permanent magnets (NPPMs)

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

Innovation
Washing Sm₂Fe₁₇N₃ with non-aqueous solvents to remove CaO reduces oxygen content and better preserves coercivity and BHmax after annealing.

Achievement
Optimized the process of removing the CaO byproduct from Sm₂Fe₁₇N₃ powders produced by the reduction-diffusion (RD) approach, reducing the oxygen content and thus preserving its magnetic properties.

Significance and Impact

• Criticality and cost: this material is mostly Fe (~74% wt.%) and non-critical rare earth Sm, as well as earth-abundant N. The RD method allows for direct synthesis from rare earth oxides, bypassing metallization.
• When fully developed, single grain-single particle Sm₂Fe₁₇N₃-based materials are expected to replace heavy rare earth Nd-based magnets in high performance, high temperature applications.

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