Abstract: With hexagonal BN （h-BN） as nitrogen source, an amorphous Fe-N alloy and ε-Fe_xNalloy with hexagonal structure were prepared by mechanical milling of Fe and h-BN. The nitrogen content change was estimated in the ε-Fe_xN alloy with milling time. We investigated the formation mechanisms and the law of structural transformation about the two kinds of alloys. Magnetic properties of the amorphous Fe-N alloy and ε-Fe_xN alloy were described by Mossbauer patterns and magnetometer of vibration samples. The results show that the magnetic property of ε-Fe_xN alloy changed from ferromagnetisium to paramagnetisium with N content increasing. The article elaborates on the law and mechanisms of the change of coercivity with boll milling time.

Key words: ε-Fe_xN alloy, mechanical milling, coercivity