Relationship between the Crystallographic Structure of Electroplated Fe-Zn Alloy Film and Its Thermal Equilibrium Diagram

The microstructures and morphology of Fe-Zn alloy electrodeposited at different chloride bath compositon are studied in detail using TEM, SEM, and XRD. And comparisons are made between microstructures in Fe-Zn alloy thus deposited and those appear in a thermal equilibrium phase diagram. The results indicate that α, Γ, Γ1, and η phase appear in the Fe-Zn electrodeposit, however δ and ζ phases which appear in the thermal equilibrium phase diagram did not appear. The surface appearance and microstructures (including grain size and lattice constant) of intermediate phases in Fe-Zn alloy electrodeposites depend on the Zn content in the Fe-Zn alloy deposit. It is also found that there is an orientation relationship among the Γ, Γ1, and η phases when these three phases appear simultaneously.