Synthesis and consolidation of iron nanopowders

A microwave plasma processing technique was used to synthesize iron nanopowders. The average particle size of these powders was similar to 10 nm and the surface area was measured to be 42 m(2)/g. Powder production rates as high as 50 gm/hour were achieved. Magnetic property measurements on iron nanopowders yielded coercivities as high as 60 kA/m at 4 K, which decreased to similar to 0 Aim (a superparamagnetic transition) at room temperature. In this paper, the microwave plasma processing technique has been compared with other nanopowder synthesis techniques. Since the successful application of nanomaterials depends highly on the processing technology, results from consolidation studies on iron nanopowders are also presented. Iron nanopowders were consolidated to study performance parameters such as density, grain growth and other morphological changes. The nanopowder was consolidated using Plasma Pressure Consolidation ((PC)-C-2) technique to 95% density, at a temperature and pressure of 850 degrees C and 63 MPa respectively Microwave plasma synthesis is capable of producing metallic and ceramic nanopowders, which will sustain interest in research areas including magnetic storage, nano-fabrication of electronic materials and nanoglass, besides the field of catalysis. (C)1999 Acta Metallurgica Inc.