Synthesis,phase study and magnetic characterisation of Co 50 Fe 40 Cu 10 ternary alloy nanopowders prepared by mechanochemical alloying process

Abstract

Mechanical milling and hydrogen reduction of pure oxide mixture and magnetic characterisation of Co–Fe–Cu ternary alloy nanopowders were investigated. A powder mixture of Co₃O₄, CuO and Fe₂O₃ with Co₅₀Fe₄₀Cu₁₀ stoichiometry was first milled by a high energy planetary ball mill and then reduced in a hydrogen reduction system.

The optimum condition of the reduction under the hydrogen atmosphere was 650°C and 1 h. The X-ray diffraction patterns exhibit that the powder has ordered bcc structure with b2–bcc space group and 2·87 Å lattice parameter. Mean crystallite sizes calculated from X-ray diffraction results and mean particle size observed from electron microscopes were over 75 nm. Magnetic evaluation of ternary alloy nanopowders showed a saturation magnetisation value about 143 Am² kg^–1 and a low coercivity value of 0·93 Am^–1.