Microwave Plasma Used for α-Fe Nanoparticles Synthesis

Pilot experiments were performed. Microwave induced plasma decomposition of iron pentacarbonyl has been used to prepare iron nanosized particles. Vapours of iron pantacarbonyl have been introduced into argon surfaguide discharge, optical emission spectra have been taken and rotational temperatures obtained. The rotational temperatures remain practically constant during the increasing of the Fe(CO)5 concentration up to total pressure 500 Pa. The intensity of (0,0) Swan band head grows. Iron nanoparticles have been produced, XRD results and TEM images were obtained. The core-shell nanoparticles were observed (size 30 nm), with α-Fe as a core and iron oxide as a shell. Introduction Magnetic properties of iron materials could be highly enhanced if particles in the nanometer size are prepared. Such particles exhibit unusual magnetic properties and could be also superparamagnetic. They also show promise for industrial applications such as catalysis, magnetic recording, magnetic fluids and biomedical applications. Several methods to produce iron particles are currrently available: laser pyrolysis of gas phase reactants [Alexandrescu et al., 1998], thermal decomposition [Burke et al., 2002], microwave plasma treatment [e.g., Brenner et al., 1997; Kalyanaraman et al., 1998], and other methods. Since such iron nanoparticles after quick exposure to air could uncontrollably oxidize and subsequently lose their specific properties, they are mostly covered by carbon, iron oxide or some kind of polymer [e.g., Burke et al., 2002; Carpenter et al., 2003]. This process is called passivation and prepared nanoparticles core-shell (e.g. iron/graphite) nanoparticles. magnetron 2.45 GHz 1 2 3