抄録
We have developed heat-stable SmFeMnN magnet powder made by reduction and diffusion method. The average particle size was 20-30μm. Slightly crushing the powder enhanced remanence of the powder, which resulted in high magnetic properties: Br: 1.12T, iHc: 597kA/m, (BH)max: 178kJ/m3. The deterioration of the coercivity was only 7% after exposure in air at 433K for 1000h. The temperature coefficient of coercivity-0.26%/K is close to that of SmCo5 magnets. On the other hand, the analysis of the structures by field emission-transmission electron microscopy (FE-TEM) and energy-dispersive X-ray (EDX) revealed that the powder was composed of nanocrystalline grains surrounded by amorphous phase. It seems that the powder shows high coercivity (-955kA/m) due to these microstructures.
