Electrodeposition of indium on copper from deep eutectic solvents based on choline chloride and ethylene glycol

The electrodeposition of Indium on Copper substrate was investigated using 0.05 mol L−1 InCl3 dissolved in a mixture of choline chloride (ChCl) and ethylene glycol (EG) in molar ratio 1:2. The In electrodeposition was controlled by diffusion and the diffusion coefficient of In3+ species in 1ChCl:2EG as a function of temperature was fitted by a like-Arrhenius equation and the apparent activation energy for the diffusion of In3+ species was 32.50 kJ mol−1. Analysis of the current-time curves using the Scharifker-Hills' model indicated that the In deposition occurred by progressive nucleation and three-dimensional growth. The morphology of the electrodeposits, obtained between 25 and 65 °C, were characterised by grains and rods in micrometer regime randomly distributed. In addition, In nanorods arrays, with diameter ranging between 75 and 250 nm, were observed in the In coating obtained at 80 °C. X-ray diffraction analysis revealed the existence of the metal In and CuIn alloy phase and that the (101) was the preferential plane to the growth of the In nanorods.