Abstract
Electrodeposition of aluminum has been investigated from solutions of aluminum bromide in cumene-ethylbenzene baths and the effects of addition of alkali halides on the cathode current efficiency were studied. The effect of the additives for brightenning and adherent aluminum deposition was: KBr≈LiBr (silver-white)>NaBr≈NaI(white)>LiCI(gray). Although the addition of theadditives increased the conductivity of the solution, the cathode current efficiency decreased. In the presence of iodide ions (LiI, NaI, KI and NH4I) in the electrolyte the tendency to form dendrites wasinhibited. It was shown by X-ray diffraction analysis that the preferred orientation of the Al depositswas strong in (111) plane. In the case of the addition of KBr and LiBr, the mean lattice constant and grain size of the deposits were found to be 4.04-4.06Å and 230-800Å, respectively. The purity of electrodeposited aluminum was more than 99.9% by emission spectrochemical analysis.
