Preparation of carbon-encapsulated iron carbide nanoparticles by an explosion method

Fe7C3 nanocrystals encapsulated in carbon nanoparticles, with sizes ranging from 10 to 40 nm, were synthesized via the explosion of a hybrid xerogel containing oxidized pitch and iron nitrate. Explosion of the hybrid xerogel was induced by heat treatment. Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) were employed to determine the structure of the nanoparticles in the explosion product. The results show that the Fe7C3 nanocrystals are nested inside amorphous carbon shells that protect them from oxidation by air. (C) 2002 Elsevier Science Ltd. All rights reserved.