Synthesis of rare earth-free Fe5C2 nanocrystals with high coercivity

CMI researchers from Ames National Laboratory conducted the activity for this highlight

Innovation
Magnetic hardening in Fe-rich carbide (rare earth-free Fe₅C₂ nanocrystals) with record coercivity of 1.6 kOe.

Achievement
Nanocrystals exhibit saturation magnetization of ~122 emu/g, and coercivity of ~1.6 kOe after alignment. The value of (BH)max is calculated to be ~4.8 MGOe. Thermal stability measurements show TC ~ 751 K and the decomposition temperature ~ 966 K.

Significance and Impact
Significant coercivity, sufficient magnetization, high Curie temperature and high thermal stability make the Fe₅C₂ nanomagnets a promising candidate for a permanent magnet.

Hub goal addressed
Prototyping of REE-reduced or REE-free permanent magnets

composite image (a) TEM image, (b) M-H loop at 300 K, (c) Demagnetizing curve with (BH)max, (d) Magnetic-TGA curve. — Figure: (a) TEM image, (b) M-H loop at 300 K, (c) Demagnetizing curve with (BH)max, (d) Magnetic-TGA curve.