Surface morphology, crystal structure and orientation of aluminium coatings electrodeposited on mild steel in ionic liquid

Galvano-static electrodeposition was used to electrodeposit aluminium on mild steel in AlCl₃/[bmim]Cl (1-butyl-3-methylimidazolium chloride) ionic liquid at variable temperatures (308-328 K). Effects of variations in current density and temperature on surface morphology and crystal orientations were systematically studied. Results show current density certainly caused changes in the morphology and deposit microstructure, and the type of deposit microstructure changed rapidly as a function of temperature, especially at higher current density. It was indicated that all of the electrodeposits exhibited a strong preferred (2 0 0) crystallographic orientation. Compared with the (2 0 0) reflection, the preferred (2 2 2) orientation was relatively weak for most samples, and under higher temperature and current density it disappears. The (1 1 1), (2 2 0), and (3 1 1) reflections were relatively weak.