Electrochemical synthesis of Ni–Sn alloys in molten LiCl–KCl

The electrochemical formation of Ni–Sn was investigated in molten LiCl–KCl in the temperature range 380–580 °C. Before, an electrochemical study of the Ni2+/Ni0, Sn4+/Sn2+ and Sn2+/Sn0 redox couples was performed by cyclic voltametry and chronopotentiometry in a wide temperature range. It had been pointed out that in the case of the Sn4+/Sn2+ redox couple, an insoluble compound is probably formed for T < 460 °C. For higher temperature, this compound becomes soluble and then, the shape of the cyclic voltammogram is analogue to the one usually observed when a diffusion-controlled process is involved. The diffusion coefficient values of Ni2+ and Sn2+ ions were determined. For instance, DNi(II) and DSn(II) values deduced from chronopotentiometry were about 2.1 × 10−5 and 2.7 × 10−5 cm2 s−1 at 440 °C, respectively. Then, Ni–Sn alloys have been formed in potentiostatic mode. The electrochemical route proposed in this paper leads to the formation of crystallized alloys with a well-defined composition depending on the operating conditions.