Iron-based Nanocomposite Synthesised by Microwave Plasma Decomposition of Iron Pentacarbonyi

摘要

A nanocrystalline iron-based powder has been prepared by microwave plasma method: Fe(CO)5 vapor was introduced into an argon discharge at ～1 kPa. A microwave 2.45 GHz generator was operated at 430 W. The reaction took place inside a quartz tube passing through a microwave waveguide. The microwave discharge (without and with Fe(CO)_5) was characterized by optical emission spectroscopy. The synthesized nanopowder was passivated in situ with air. The as-prepared nanopowder was characterized by TEM, XRD, Raman and Mossbauer spectroscopies. The nanopowder included a-Fe, a-Fe_2O_3, and Fe3O4 phases. The core-shell nanoparticles were observed under TEM: a-Fe cores had shells formed of Fe_3O_4 or carbon. The mean crystallite size of a-Fe was 36 ran (Scherrer formula). The synthesized nanopowder exhibited ferromagnetic behavior.