Changes of structure and magnetic properties for a mixture of α-Fe and Fe3N powders during mechanical alloying process

Abstract

The X-ray diffraction was used to monitor the structural changes of a mixture of α-Fe and Fe3N powders during the ball milling. Changes of saturation magnetization of the powder mixture were also measured. The results showed that Fe3N decomposed quickly and then disappeared with increasing milling time, some N atoms soluted in α-Fe. After milling for about 30 h, a stable supersaturated solid solution with N content of about 0.290–0.346 wt% was obtained. The grain size decreased with increasing milling time and reached a constant of about 8 nm after about 30 h milling. The saturation magnetization of the powder mixture initially decreased, but began to increase when milling time exceeded 5 h, and finally reached a constant value when milling time exceeded 30 h.