Electrodeposition of transition metal aluminum alloys from molten AlCl3-NaCl.

The electrodeposition of cobalt, copper, iron, and nickel was investigated in the Lewis acidic AlCl3-NaCl (60.0-40.0 mole %) molten salt at 160 degrees C. Cyclic and sampled current voltammetry (SCV) experiments at polycrystalline tungsten electrodes in melts containing Co(II), Cu(I), Fe(II), and Ni(II) indicated that it was possible to deposit each of these metals under diffusion-controlled conditions. At more negative potentials, but positive of the potential at which the bulk deposition of aluminum is normally observed (0 V versus the Al(III)/Al couple), aluminum co-deposits with each of these metals to form alloys. The underpotential co-deposition of aluminum commenced at 0.46, 0.34, 0.32, and 0.58 V during the deposition of cobalt, copper, iron, and nickel, respectively. The results of this investigation suggest that it may be possible to electrodeposit Co-Al, Fe-Al, and Ni-Al alloys containing up to 45 atomic percent (a/o) aluminum and Cu-Al alloys containing up to 60 a/o aluminum from this melt at potentials greater than or equal to 0 V.