Sonochemical preparation of nanosized amorphous Fe-Ni alloys

Nanosized amorphous alloy powders of Fe20Ni80, Fe40Ni60, and Fe60Ni40 sonochemical decomposition of solutions of volatile organic precursors, Fe(CO)(5) and Ni(CO)(4) in decalin, under an argon pressure of 100 to 150 kPa at 273 K. Magnetic susceptibility of Fe40Ni60 and Fe60Ni40 indicates blocking temperatures of 35 K and a magnetic particle size of about 6 nm. Thermogravimetric measurements of Fe20Ni80 give Curie temperatures of 322 degrees C for amorphous and 550 degrees C for crystallized forms. Differential scanning calorimetry exhibits an endothermic transition at 335 degrees C from a combination of the magnetic phase transition and alloy crystallization. The Mossbauer spectrum of crystallized Fe20Ni80 shows a sextet pattern with a hyperfine field of 25.04 T. (C) 1997 American Institute of Physics.