Morphology of Electrodeposited Zn/Fe Crystals.

Zn/Fe alloy electrodeposition on a low carbon steel sheet has been examined mainly by means of scanning electron microscopy and X-ray diffraction. The results obtained are as follows: The crystal structure and the morphology of the film deposited in a low Fe bath changes from granular η/Γ mixed phases, to pyramidal η-phase crystals and then to layered hexagonal η-phase plates with increasing current density. The initial deposits on the substrates, however, are layered hexagonal η-phase plates at all the current densities examined. The final morphology is determined by the deposits on these η-phase crystals. The c/a ratio of η-phase varies from 1.87 to 1.63 with increasing Fe concentration in the crystals. The morphological change of η-phase crystals can be explained in terms of the atomic configurations on both (0001)η and {1100}η planes and the c/a ratio. In the case of a high Fe bath, the deposited film is varied from granular η/Γ to cuboidal Γ/Γ1 mixed phases with increasing current density.