Synthesis and characterization of nanowires formed by self-assembled iron particles

Abstract

The formation of iron particles without and with carbon coating was studied in a hot wall flow reactor. The precursors ironpentacarbonyl (IPC, Fe(CO)5) and ethylene (C2H4) both diluted in N2 were used in a concentric tubular flow arrangement and were heated to temperatures between 570 and 1170 K at pressures between 50 and 500 mbar. In experiments without C2H4, either individual iron particles in the size range of or long iron chains composed of several hundreds of individual iron particles were found depending on the reaction conditions. In experiments with C2H4 addition, these particles or particle chains were covered by a thin carbon/carbide layer. The size of the primary particles was measured in situ by time-resolved laser-induced incandescence (TR-LII) and ex situ by rapid thermophoretic particle probing and TEM imaging.

Flame spray synthesis under a non-oxidizing atmosphere: Preparation of metallic bismuth nanoparticles and nanocrystalline bulk bismuth metal

“…Similarly, mixtures of soot, carbon nanotubes and metallic nanoparticles were obtained from acetylene flames and an iron-carbonyl precursor (Height et al, 2004). These observations and recent reports on the gas phase reduction of copper (Nasibulin et al, 2001;Nasibulin et al, 2005), iron (Knipping et al, 2004) and nickel (Suh et al, 2005) indicate the possibility of manufacturing metallic nanoparticles in highly reducing flames.…”

Structure and magnetic properties of iron nanoparticles stabilized in carbon

“…The last produces a material similar to this study but in a heterogenous way with no control over particle size and size distribution. 23 Iron oxides are usually formed at the surface of these particles. Chemical vapor synthesis is a modified chemical vapor deposition ͑CVD͒ process where the process parameters are adjusted to generate fine particles instead of thin film growth.…”

Preparation and properties of nanostructured magnetic hollow microspheres: experiment and simulation

“…On the other hand, antiparallel alignment is preferred when the distance vector points perpendicular to the orientation of the moments. Therefore, free particles tend to agglomerate in chain structures, as can be observed in experiments [19,20,28]. Since such a configuration is not possible on a surface of a sphere, at low temperatures the typical vortexlike moment structure evolves with moments aligned parallel to the surface of the sphere further stabilising the shell structure and leading to a vanishing overall magnetic moment of the system (for a detailed review on the magnetic properties of mainly dipolar coupled magnetic nanosystems see [29]).…”