Electrochemical behavior and electrodeposition of cobalt from choline chloride-urea deep eutectic solvent

The electrochemical behavior and electrodeposition of cobalt was investigated in the choline chloride-urea deep eutectic solvent containing cobalt chloride. Cyclic voltammetry was used to study the effect of temperature and concentration on the electrochemical behavior of cobalt. Chronoamperometry results show that as the applied potential increases, the electrocrystallization of cobalt on the tungsten electrode gradually tends to three-dimensional instantaneous nucleation. SEM observation of the microstructure of the coating shows that the deposited films obtained in this experimental condition (-0.85 V similar to -1.0 V; 343 K-373 K) are dense and uniform with fine crystals. As the deposition potential increases, the contours of the particles are become clear and the edges of the particles gradually join. As the temperature rises, the coating particles increase to become gradually uniform, the plush contour gradually disappears, and the particles are no longer connected with the other particles. EDS and XRD analyses show that pure cobalt coating was obtained. (C) 2018 Elsevier Ltd. All rights reserved.