Structure and magnetic properties of spinodal decomposed Cu60Ni20Fe10Co10 ribbons with hard magnetism

The spinodal decomposed Cu-Ni-Fe alloy can possess both hard magnetic properties and excellent plastic toughness, corrosion resistance, and cold workability. Cu₆₀Ni₂₀Fe₁₀Co₁₀ ribbons are prepared by melt-spinning and annealing methods, and their phase composition, microstructure, and magnetic properties are studied. The results show that the as-spun ribbons are composed of equiaxed grains. Through the decomposition of γ → γ₁ + γ₂ inside the grains, the spinodal structure is formed, which endows the ribbons with the hard-magnetic properties. Also, the maximum coercivity of 679.3 ± 149.1 Oe and saturation magnetization of 72.0 ± 2.7 emu/g are obtained in the ribbons annealed at 435 °C for 30 min and 835 °C for 30 min, respectively. The shape anisotropy of γ₁ and γ₂, the concentration of Fe, Co, Ni in the γ₂ phase, and the content of the α phase are the main factors to determine the magnetic properties. At the same time, the corresponding microstructure evolution models are proposed.