Compaction of ??-Fe16N2 particles by high-pressure treatment at several gigapascals

Demands for a high-performance magnet that is rare earth-free and composed of abundant elements is increasing. alpha-Fe16N2 is one of the possible candidates for permanent magnet material superior to ferrite and Al-Ni-Co magnets. The resulting alpha-Fe16N2 powder should be made into a high-density bulk to obtain high magnetic properties. Here, we applied high-pressure (HP) and high-temperature (HT) treatment for compaction of alpha-Fe16N2 powders. Our study revealed that treatment in the range of 1 to 3 GPa with moderate temperature gives dense alpha-Fe16N2 pellets. We also found that the pelletized sample maintained its magnetic properties for 100 days due to the suppression of gradual decomposition in the air.

Automated summary

The demand for a high-performance magnet made of abundant elements without rare earth is increasing. Alpha-Fe16N2 shows promising potential as a superior permanent magnet material compared to ferrite and Al-Ni-Co magnets. By applying high-pressure and high-temperature treatment, we successfully achieved dense alpha-Fe16N2 pellets. These pelletized samples maintained their magnetic properties for 100 days due to the suppression of gradual decomposition in the air.