Synthesis and magnetic properties of Fe-Co-Ni nanoparticles by hydrogen plasma-metal reaction

Nanoparticles of Fe-Co-Ni ternary alloys were prepared in six compositions by hydrogen plasma-metal reaction. Structures, particle features, oxidation behaviors and magnetic properties of the nanoparticles were investigated by XRD, TEM, DSC and SQUID. The nanoparticles having mean particle diameters of 34-43 nm can be prepared with desired composition in the whole range. The phase and magnetic diagrams for the nanoparticles have been drawn in the ternary alloys. The nanoparticles have nearly the same crystalline structures and lattice constants as those of the corresponding bulk alloys. The nanoparticles exhibit a ferromagnetism similar to the bulk alloys. The saturation magnetization is 10-30% lower, but the coercive force is much larger than those of the bulk alloys. (C) 2000 Elsevier Science B.V. All rights reserved.