Synthesis and characterization of highly magnetized nanocrystalline Co30Fe70 alloy by chemical reduction

Co30Fe70 nanoparticles with mean particle size of about 8 nm were successfully synthesized by the chemical reduction of cobalt chloride and iron chloride with borohydride as a reducing agent in aqueous solution. The composition and size of the Co30Fe70 nanoparticles were optimized by controlling the molar ratio of starting materials, reaction time, and dropping rate of aqueous reducing agent. As alloy powders prepared by chemical reduction tend to be amorphous in the as-synthesized state, the as-precipitated Co30Fe70 nanoparticles were heat-treated to achieve crystallinity at the different temperatures for 1 h. The Co30Fe70 nanocrystallite by chemical reduction shows excellent soft magnetic behavior, such as high permeability, negligible coercivity, and high saturation magnetization like that of Co30Fe70 bulk.