Synthesis and characterization of iron carbonitride ultrafine particles

Iron carbonitride (ICN) ultrafine particles (20-80 nm in size) have been synthesized by laser-induced pyrolysis of Fe(CO)₅-NH₃-C₂H₄ mixture. The surface morphology, structural characteristics, oxidation behavior, and the magnetic properties of the ICN particles were reported. The role the thin carbon layer formed on the particle surface played in the oxidation behavior and in the enhancement of the magnetic properties has been studied. A carbon layer (1-2 nm) seems to protect the particles effectively from reaction of the iron carbonitride with oxygen, and the ICN particles thereby exhibit a high saturation magnetization of 142 emu/g. Additionally, the unilateral lattice expansion of the ICN compound was interpreted in terms of the structural and chemical bonding features of the ICN compound.