Synthesis of FeNi₃ alloyed nanoparticles by hydrothermal reduction

The present paper presents a facile and low-cost hydrothermal method to synthesize stoichiometric FeNi₃ alloy nanoparticles by reducing Ni(NO₃)₂·6H₂O and Fe(NO ₃)₂·6H₂0 with hydrazine hydrate in strong alkaline media. X-ray diffraction patterns of as-prepared samples synthesized at 180 °C for different hydrothermal reaction times reveal that the products are pure stoichiometric FeNi₃ alloyed nanoparticles with well-defined crystalline cubic structure when the hydrothermal time is above 2 h, while no crystal phases are detected in the product obtained under ambient pressure in an open system from the same starting prescription. Transmission electron microscopic images show that the size of the as-prepared nanoparticles increases with prolongation of the hydrothermal reaction time. The as-prepared sample has the symmetric hysteresis loop behavior of ferromagnetic materials.