Synthesis and consolidation of iron nanopowders

A microwave plasma processing technique was used to synthesize iron nanopow ders. The average particle size of these powders was similar to 10 nm and t he surface area was measured to be 42 m(2)/g. Powder production rates as hi gh as 50 gm/hour were achieved. Magnetic property measurements on iron nano powders 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 t his 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 co nsolidation studies on iron nanopowders are also presented. Iron nanopowder s were consolidated to study performance parameters such as density, grain growth and other morphological changes. The nanopowder was consolidated usi ng 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 o f catalysis. (C)1999 Acta Metallurgica Inc.