Abstract
Electrowinning of iron was conducted in a 50 wt% NaOH-H2O electrolyte with suspended Fe2O3 particles at 110ºC and pure α-Fe films were obtained on a disk cathode with a higher current efficiency than 95%. The Fe2O3 particle was directly reduced on the surface of the disk cathode, and the deposited Fe atoms formed cubic particles with a side length of approximately 0.1 μm. The crystal orientation of α-Fe depends on electrolysis conditions, such as current density and Fe2O3 particle content, and the (211) face plane of α-Fe was preferentially orientated. Therefore, a cubic α-Fe particle grows in a columnar formation toward the (211) face direction by spiral dislocation after two-dimensional nucleation. Furthermore, the morphology of the obtained α-Fe film can be controlled by the current density and the transfer rate of the Fe2O3 particles.