Gas phase preparation of spherical core–shell α′′-Fe16N2/SiO2 magnetic nanoparticles

Abstract

Well-dispersed spherical core–shell α′′-Fe₁₆N₂/SiO₂ ferro-magnetic nanoparticles were successfully synthesized from core–shell α-Fe/SiO₂ nanoparticles. Introduction of oxidation prior to the nitridation process gives 90% of α′′-Fe₁₆N₂ phase contained in the core while no phase change is observed without oxidation. Saturation magnetization and coercivity are 148 emu g⁻¹ and 1.82 kOe, respectively.