Aluminum was electrodeposited onto metallic substrates from a number of electrolytes consisting essentially of an AlBr3 solute of commercial purity and technical grade alkylbenzene solvents or solvent mixtures.Bright, fine grained, and adherent aluminum coatings 0.5 mil (.013 mm) thick were obtained at cathode efficiencies of the order of 70-85% and at anode efficiencies approaching 100%. The best electrolytes have been found to be those based upon ethylbenzene and diethylbenzene solvents with toluene as a less expensive diluent.The electrolytes have been found to operate most efficiently and reproducibly at specific conductances between 3.0 and 4.0 x 10 -3 fi -lcm -1.The conductance can be maintained at these levels by the periodic addUion of HBr gas.A cell for studying the polarization behavic.ur of organic-based electrolytes was developed and was used to determine cathode charge transfer overvoltages for the ethylbenzene-toluene (1: 1 volume), AlBr3 (50 wt. %) electrolytes. The charge transfer overvoltage was found to be 40 mV at current densities of 10 mAI cm 2 and the heats of activation for the electrodeposition process were of the order of 4 Kcal/ mole (27 to 67 0 C). EX)Jerimental Tafel plots ingicated that the electrodeposition process takes place in steps of 3 electrons. The ions responsible for the plating of aluminum are thought to be TT ,hydroxy 17 and bromo TT complexes. Name: