Nanoscale powders of different iron oxide phases prepared by continuous laser irradiation of iron pentacarbonyl-containing gas precursors

Different iron oxide-based nanosized powders were obtained by the IR laser synthesis from gas phase reactants by using iron pentacarbonyl vapor as iron donor. In the flowing gas mixture, oxidizers (like nitrous oxide and air) and sensitizers (like sulfur hexafluoride and ethylene) have been used. A major amount of gamma-Fe2O3 was obtained after a series of experiments in which alpha-Fe2O3 and iron fluorides were the dominant phases. The mean size of the obtained gamma-iron oxide particles was in the range 3-7 nm. The structural characterization of the new elaborated materials points out to the crucial influence that the experimental parameters (particularly the combined choice of the oxidizer/sensitizer agents) have on the specific oxide phase formation as well as on its purity. (C) 2002 Elsevier Science B.V. All rights reserved.