Composition and structure of Al-Sn alloys formed by constant potential electrolysis in an AlCl(3)-NaCl-KCl-SnCl(2) molten salt

To form Al-Sn alloys for bearing materials, molten salt electrolysis was performed in an AlCh-NaCl-KCl molten salt containing SnCl(2) at 423 K. The voltammogram showed that the cathodic reduction of the Sn ions started at a potential of 0.5 V vs. A1/A1(III) in the molten salt showing that deposition of pure Sn was possible at 0.5 V. Co-deposition of Al and Sn occurred at potentials more negative than 0.1 V. The co-deposit was composed a solid solution of Al and Sn. The ratio of the Sn in the electrodeposits decreased with the potential from 100 at.% at 0.2 V to 19 at.% at -0.3 V. In the structural observations, electrodeposits with an alternate stacked structure of Al and Sn is obtained at -0.075 V.