Peter Zelina

Versatile low-pressure plasma-enhanced process for synthesis of iron and iron-based magnetic nanopowders

Using microwave low-pressure discharge, we synthesised magnetic iron-oxide nanopowder from the iron pentacarbonyl precursor. We were able to vary the size and chemical composition (especially the ratio between various iron oxides) by careful control of the process parameters. The nanoparticulate product was analysed by X-ray diffraction (XRD) and Raman spectroscopy. However, the XRD cannot reliably distinguish between the size-broadened peaks of γ-Fe2O3 (maghemite) and Fe3O4 (magnetite) due to their nearly identical crystalline structure. Hence we used a chemical method to determine the presence of Fe(II) and Fe(III) ions in the nanopowder samples. The results agree with those from the Raman spectroscopy.

Optical Diagnostics of Iron Oxide Nanoparticle Synthesis in Microwave Oxygen Plasma

Iron oxide nanoparticle synthesis in microwave plasma is studied by optical diagnostics. The arrangement of the plasma reactor results in well-defined reactant mixing, which makes different parts of the reaction zone clearly observable. Besides the reaction zone, digital imaging also reveals the presence of heated nanoparticles. The optical emission spectroscopy is used to determine important plasma parameters.