Formation of Iron-Nitride/Silver Nanocomposites by Ammonia-Flow Method and Nitride Phase Identification by X-Ray Absorption Near-Edge Structure

Magnetic nanocomposites in which iron nitride nanograins were dispersed in a silver matrix were synthesized by nitriding iron oxide nanograins buried in the matrix. The ammonia-flow method, in which the solid phase reacted with flowing ammonia, was adopted for this synthesis. Several reactions of metallic iron with NH 3 were carried out under various conditions and the resultant nitride phases were observed by X-ray diffraction (XRD). Based on these results, optimum conditions for the synthesis of the nanocomposite were determined, and a nanocomposite containing only γ'-Fe 4 N or ε -Fe 2–4 N was successfully obtained. Phase identification of iron nitride in the composite was performed by X-ray absorption near-edge structure (XANES) measurement, which was found to be more suitable for the present nanocomposites than XRD.