Using a ball-milling technique,polymorphous iron particles were prepared by changing only the liquid-solid ratioλ.Effects of λon their morphology,structure,conductivity,and electromagnetic properties were studied.The results show that an increase ofλfrom 0 to 0.25 causes a nonlinear decrease of the conductivity in the ranges of 88.50-2.25 S cm-1 and a regular variation of the electromagnetic parameters,corresponding to the as-obtained iron particles.This is ascribed to a combination of the increased shape anisotropy and the decreased fresh surface with active atoms deriving from the weakened welding-on action and the enhanced micro-malleation action in the ball-milling process.Hereinto,the iron flakes formed at wet-milling with λ=0.08-0.25 have lower conductivity,higher permittivity and permeability,and more excellent absorption property compared with the irregular iron particles obtained at dry-milling withλ=0.It is a consequence of the synergistic effect of dielectric relaxation loss,exchange energy and conductance loss originating from the flake-shape structures.This indicates that the morphology,structure,conductivity,and electromagnetic properties of the products can be effectively controlled by changingλ. Using a ball-milling technique, polymorphous iron particles were prepared by changing only the liquid-solid ratio λ. Effects of λon their morphology, structure, conductivity, and electromagnetic properties were studied. The results show that an increase of λfrom 0 to 0.25 causes a nonlinear decrease of the conductivity in the ranges of 88.50-2.25 S cm-1 and a regular variation of the electromagnetic parameters, corresponding to the as-obtained iron particles. this is ascribed to a combination of the increased shape anisotropy and the decreased fresh surface with active atoms deriving from the weakened welding-on action and the enhanced micro-malletion action in the ball-milling process. Hereinto, the iron flakes formed at wet-milling with λ = 0.08-0.25 have lower conductivity, higher permittivity and permeability, and more excellent absorption property compared with the irregular iron particles obtained at dry-milling with λ = 0.It is a consequence of the synergistic effect of dielectric relaxation loss, exchange energy and conductance loss originating from the flake-shape structures. This indicates that the morphology, structure, conductivity, and electromagnetic properties of the products can be effectively controlled by changing λ.