Electrodeposition of Al-W-Mn Ternary Alloys from the Lewis Acidic Aluminum Chloride−1-Ethyl-3-methylimidazolium Chloride Ionic Liquid

Abstract

The electrodeposition of non-equilibrium ternary Al-W-Mn alloys was examined in the Lewis acidic 66.7-33.3 m/o aluminum chloride–1-ethyl-3-methylimidazolium chloride (AlCl3–[C2mim]Cl) ionic liquid (IL). K3[W2Cl9] and MnCl2 were added to provide sources of W and Mn. The Al-W-Mn alloys were deposited on Cu wire substrates rotated at a fixed rate of 1000 rpm by using a dc galvanostatic method. The W content in the ternary Al-W-Mn alloys decreased with an increase in the deposition current density and was independent of the K3[W2Cl9] and MnCl2 concentrations in the plating solution. However, both the current density and the metal salt concentrations affected the Mn content of the ternary alloys. X-ray diffraction and composition analysis of the resulting Al-W-Mn deposits revealed the presence of an amorphous non-equilibrium alloy phase without chloride contamination. The chloride-induced pitting potential of the Al-W-Mn ternary alloys was found to be superior to that of the related binary alloys, Al-W and Al-Mn, indicating that the presence of two transition metal solutes has a beneficial additive effect on the corrosion resistance of Al.