Influence of temperature on the electrochemical formation of a Ni-Co alloy under an applied external magnetic field

This work reports for the first time the influences of temperature and of an external magnetic field on the mechanics and kinetics of the electrochemical nucleation and growth of the nickel–cobalt alloy during its potentiostatic electrodeposition onto a glassy carbon electrode (GCE) surface, from its precursor ions dissolved in the deep eutectic solvent (DES) formed by the eutectic mixture of choline chloride and urea (reline). The analysis of the potentiostatic current density transients was carried out using the Díaz-Morales et al., model [O. Díaz-Morales, J. Mostany, C. Borrás, and B. R. Scharifker, J. Solid State Electrochem., 2 (2013) 345–351], developed for the kinetics of nucleation and diffusion-controlled growth of bimetallic phases. It was found that at a constant temperature and applied potential, the presence of the magnetic field increases the nucleation kinetics parameters: the nucleation frequency (A) of the Ni-Co alloy and the number density of active sites (N0). From the characterization of the electrodeposits formed by means of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), it was found that the nuclei formed comprised the Ni-Co alloy, though in addition, the morphology of the bimetallic particles was modified by applying the external magnetic field.