Chemical synthesis of α-iron in aqueous FeCl3

Iron–aluminium composite and α-iron powder have been prepared by chemical reduction of aqueous FeCl3 with aluminium at different conditions. Experiments showed that the concentration of FeCl3 and aluminium particle size are the main factors to influence the reaction. XRD, SEM and potentiometric titration were employed to characterize the products. SEM showed that as iron particles grow they tend to form spherical seed on the surface of aluminium. XRD revealed that the α-iron was single phase after deposit treatment by NaOH solution. The purity of as-prepared α-iron was 99.5%, as determined from the X-ray fluorescence spectroscopy. The possible formation mechanism is a two-stage red–ox-process: Fe3+→Fe2+→α-Fe.