Synthesis and structural investigation of ɛ-Fe3−xNixN (0.0 ≤ x ≤ 0.8) nanoparticles

ɛ-Fe3−xNixN (0.0 ≤ x ≤ 0.8) system is synthesized by precursor technique and nitridation of the Fe–Ni-oxide nanoparticles in NH3 (g). For x = 0.0–0.4, single phase ɛ-Fe3N hexagonal structure with space group P63/mmc is obtained, while for x = 0.5–0.8, a mixture of hexagonal ɛ-Fe3−xNixN and fcc γ′-Fe4−yNiyN phases are observed. Rietveld analysis is shown for the representative ɛ-Fe2.6Ni0.4N and ɛ-Fe2.2Ni0.8N compositions and it is observed that Ni substitutes the Fe atoms randomly and the metal atoms occupy [1/3, 2/3, 1/4] and [2/3, 1/3, 3/4] positions while the N atoms occupy [0, 0, 0] and [1/3, 2/3, 1/2] positions. Electron microscopy and atomic force microscopy confirm the nanostructured and spherical/platelet nature of the particles.