The purpose of this research was to make an exploratory investigation of organic solutions containing the compounds aluminum bromide, aluminum stearate, basic aluminum acetate, aluminum phenoxide, aluminum o-nitrophenoxide, and aluminum acetylacetonate to determine if these compounds will furnish aluminum ions for electrodeposition.

A review of the literature revealed that the ability of aluminum to resist corrosion by the atmosphere and many chemicals led to an extensive investigation of possible methods for electroplating aluminum on base metals.

All of the studies on the electrodeposition of aluminum may be classified into four systems: aqueous solutions, nonaqueous organic liquid solutions, nonaqueous inorganic liquid solutions, and fused salts mixtures. Aluminum halides, especially aluminum chloride and bromide, probably have been the most frequently used solutes. One of the disadvantages of using a system containing aluminum halides is that these compounds pick up moisture readily from the atmosphere, and electrolysis results in the decomposition of the water with evolution of hydrogen at the cathode instead of electrodepositing aluminum.

In the initial experiments, electrolyses were performed so that observations could be made of an aluminum deposit obtained from a nonaqueous liquid organic system and the conditions for electrodeposition. Current densities of 0.379 to 0.9 amperes per square decimeter were employed with a bath containing 5.067 grams of aluminum foil, and 110 and 70 millimeters of ethyl bromide and benzene, respectively. The aluminum anode replenished the bath with aluminum which was electrodeposited on a copper cathode. Four deposits were obtained in these electrolyses but they indicated that this bath has poor throwing power and it is extremely sensitive to a change in current density.

The second series of experiments consisted of solubility tests with aluminum stearate in various organic solvents, and conductivity tests with the system aluminum stearate-ethyl phosphate-addition compounds. The addition of 0.4 gram of stearic acid and 0.8 gram of lithium stearate to a bath of 0.2 gram of aluminum stearate in 74.6 grams of ethyl phosphate resulted in the greatest increase in current obtained with any of the addition agents tested. Using platform electrodes one inch apart, the current increased from 0 to 5.3 milliamperes at 50 volts potential. These experiments were discontinued because of the low solubility of aluminum stearate in typical organic solvents and insufficient current for practical use.

The third series of experiments consisted of solubility tests with basic aluminum acetate and electrolyses of the system basic aluminum acetate and formamide. Various types of organic solvents were tested but only formamide dissolved the basic aluminum acetate. Electrolysis of a bath containing 2.5 grams of basic aluminum acetate and 79.1 grams of formamide for 11.33 hours resulted in the formation of an unidentified precipitate in the bath and around the aluminum anode and copper cathode. This work was discontinued since gases were evolved and both electrodes and the current decreased from 100 to 35 milliamperes during electrolysis.

In the fourth group of experiments, aluminum phenoxide, aluminum o-nitrophenoxide, sodium phenoxide, and sodium phenoxide, and sodium o-nitrophenoxide were prepared for use as mixed electrolytes. From the results of solubility tests with these compounds, the following systems were prepared and electrolyzed: 15 grams of aluminum o-nitrophenoxide, 1.5 grams of sodium o-nitrophenoxide, and 45 grams of methyl alcohol; 8 grams of aluminum phenoxide, 0.5 grams of sodium o-nitrophenoxide, and 106.1 grams of ethyl phosphate; 8 grams of aluminum phenoxide, 0.4 gram of sodium phenoxide, and 106.1 grams of ethyl phosphate. Using a combination of either a platinum anode and copper cathode or an aluminum anode and copper cathode, no aluminum was obtained in 1 to 6 hours of electrolysis at potentials of 8 to 50 volts. This work was discontinued because of evidence, in the form of heavy crust-like deposits on the electrodes, that the passage of current resulted in organic reactions.

The final group of experiments consisted of the preparation of the acetylacetonates of aluminum and sodium for use as a mixed electrolyte, solubility tests in various types of organic solvents, and conductivity tests with several solutions. Conductivity tests at 10 to 30 volts potential across an aluminum anode and copper cathode, spaced one-half inch apart, showed no passage of current through three baths; each of the three solutions contained 0.2 to 0.3 gram of aluminum acetylacetonate in 9.2 grams of dimethyl glycol monobutyl ether, 7.9 grams of absolute alcohol, or 21.3 grams of ethyl phosphate, respectively. Since no current was observed in these tests, work with the acetylacetonates of aluminum and sodium was discontinued.