Effect of Ambient Gas Temperature on Synthesis of Fe-N Nanosized Powders by Pulsed Wire Discharge

Abstract

Fe-N nanosized powders successfully were synthesized in ambient ammonia (NH₃) gas at different temperature by pulsed wire discharge (PWD). The powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results of XRD revealed that the powders synthesized from room temperature (R.T.) to 450 °C was α-Fe, γ-Fe(N), γ'-Fe₄N and ε-Fe₃N. The volume fraction of γ-Fe(N) decreased rapidly above 300 °C. On the contrary, those of α-Fe and γ'-Fe₄N were increased. The volume fraction of ε-Fe₃N was independent on ambient gas temperature. The median size of the synthesized powder observed by TEM increased with increasing ambient gas temperature.